ETH Price: $2,441.38 (-0.21%)

Transaction Decoder

Block:
16632265 at Feb-15-2023 06:09:47 AM +UTC
Transaction Fee:
0.008288148180876498 ETH $20.23
Gas Used:
274,318 Gas / 30.213650511 Gwei

Emitted Events:

171 GnosisSafeProxy.0x3d0ce9bfc3ed7d6862dbb28b2dea94561fe714a1b4d019aa8af39730d1ad7c3d( 0x3d0ce9bfc3ed7d6862dbb28b2dea94561fe714a1b4d019aa8af39730d1ad7c3d, 0x000000000000000000000000000000000000ad05ccc4f10045630fb830b95127, 000000000000000000000000000000000000000000000000001f710732432000 )
172 Land.Approval( owner=0xb7737576929afd9445fce22bce9f929779896da9, approved=0x00000000...000000000, tokenId=98253 )
173 Land.Transfer( from=0xb7737576929afd9445fce22bce9f929779896da9, to=[Sender] 0xa43d1d06ed27632f94be1337216a414c9b515dfa, tokenId=98253 )
174 ERC1967Proxy.0x61cbb2a3dee0b6064c2e681aadd61677fb4ef319f0b547508d495626f5a62f64( 0x61cbb2a3dee0b6064c2e681aadd61677fb4ef319f0b547508d495626f5a62f64, 0x000000000000000000000000b7737576929afd9445fce22bce9f929779896da9, 0x000000000000000000000000a43d1d06ed27632f94be1337216a414c9b515dfa, 0000000000000000000000000000000000000000000000000000000000000080, fb5cf92f1741a4f03cb31e7740570f45f1427e6c59ad5db0d55538b8c613f020, 00000000000000000000000000000000000000000000000000000000000002c0, 3c51483770d78fc79dd0221bbeb421377b954188f15155b52e2bc89fc0a134a2, 000000000000000000000000b7737576929afd9445fce22bce9f929779896da9, 0000000000000000000000000000000000000000000000000000000000000001, 0000000000000000000000000000000000dab4a563819e8fd93dba3b25bc3495, 00000000000000000000000034d85c9cdeb23fa97cb08333b511ac86e1c4e258, 0000000000000000000000000000000000000000000000000000000000017fcd, 0000000000000000000000000000000000000000000000000000000000000001, 0000000000000000000000000000000000000000000000000000000000000000, 00000000000000000000000000000000000000000000000018904d9f44710000, 0000000000000000000000000000000000000000000000000000000063ec60fe, 0000000000000000000000000000000000000000000000000000000063f0557e, 00000000000000000000000000000000000000000000000000000000000001a0, 00000000000000000000000000000000e683fd4bea07846cee3359c91c7c37a4, 0000000000000000000000000000000000000000000000000000000000000200, 0000000000000000000000000000000000000000000000000000000000000001, 0000000000000000000000000000000000000000000000000000000000000032, 00000000000000000000000037ceb4ba093d40234c6fb312d9791b67c04ef49a, 0000000000000000000000000000000000000000000000000000000000000001, 0100000000000000000000000000000000000000000000000000000000000000, 000000000000000000000000a43d1d06ed27632f94be1337216a414c9b515dfa, 0000000000000000000000000000000000000000000000000000000000000000, 0000000000000000000000000000000000dab4a563819e8fd93dba3b25bc3495, 00000000000000000000000034d85c9cdeb23fa97cb08333b511ac86e1c4e258, 0000000000000000000000000000000000000000000000000000000000017fcd, 0000000000000000000000000000000000000000000000000000000000000001, 0000000000000000000000000000000000000000000000000000000000000000, 00000000000000000000000000000000000000000000000018904d9f44710000, 0000000000000000000000000000000000000000000000000000000063ec60ff, 0000000000000000000000000000000000000000000000000000000063ec84ff, 00000000000000000000000000000000000000000000000000000000000001a0, 00000000000000000000000000000000973120267914ddd2637b3a201a11963e, 00000000000000000000000000000000000000000000000000000000000001c0, 0000000000000000000000000000000000000000000000000000000000000000, 0000000000000000000000000000000000000000000000000000000000000001, 0100000000000000000000000000000000000000000000000000000000000000 )

Account State Difference:

  Address   Before After State Difference Code
0x00000000...830B95127
(Blur.io: Marketplace)
0x34d85c9C...6E1C4E258
0x37ceB4bA...7c04eF49A 248.648118590287373634 Eth248.656968590287373634 Eth0.00885
(beaverbuild)
119.881566110790743183 Eth119.881840428790743183 Eth0.000274318
0xA43d1D06...c9B515dfA
4.6 Eth
Nonce: 0
2.821711851819123502 Eth
Nonce: 1
1.778288148180876498
0xb7737576...779896dA9 3.201381991524433185 Eth4.962531991524433185 Eth1.76115

Execution Trace

ETH 1.77 ERC1967Proxy.9a1fc3a7( )
  • ETH 1.77 BlurExchange.execute( sell=[{name:order, type:tuple, order:1, indexed:false, value:[{name:trader, type:address, order:1, indexed:false, value:0xb7737576929aFd9445fcE22bcE9F929779896dA9, valueString:0xb7737576929aFd9445fcE22bcE9F929779896dA9}, {name:side, type:uint8, order:2, indexed:false, value:1, valueString:1}, {name:matchingPolicy, type:address, order:3, indexed:false, value:0x0000000000daB4A563819e8fd93dbA3b25BC3495, valueString:0x0000000000daB4A563819e8fd93dbA3b25BC3495}, {name:collection, type:address, order:4, indexed:false, value:0x34d85c9CDeB23FA97cb08333b511ac86E1C4E258, valueString:0x34d85c9CDeB23FA97cb08333b511ac86E1C4E258}, {name:tokenId, type:uint256, order:5, indexed:false, value:98253, valueString:98253}, {name:amount, type:uint256, order:6, indexed:false, value:1, valueString:1}, {name:paymentToken, type:address, order:7, indexed:false, value:0x0000000000000000000000000000000000000000, valueString:0x0000000000000000000000000000000000000000}, {name:price, type:uint256, order:8, indexed:false, value:1770000000000000000, valueString:1770000000000000000}, {name:listingTime, type:uint256, order:9, indexed:false, value:1676435710, valueString:1676435710}, {name:expirationTime, type:uint256, order:10, indexed:false, value:1676694910, valueString:1676694910}, {name:fees, type:tuple[], order:11, indexed:false}, {name:salt, type:uint256, order:12, indexed:false, value:306407767383169205770376005618740508580, valueString:306407767383169205770376005618740508580}, {name:extraParams, type:bytes, order:13, indexed:false, value:0x01, valueString:0x01}], valueString:[{name:trader, type:address, order:1, indexed:false, value:0xb7737576929aFd9445fcE22bcE9F929779896dA9, valueString:0xb7737576929aFd9445fcE22bcE9F929779896dA9}, {name:side, type:uint8, order:2, indexed:false, value:1, valueString:1}, {name:matchingPolicy, type:address, order:3, indexed:false, value:0x0000000000daB4A563819e8fd93dbA3b25BC3495, valueString:0x0000000000daB4A563819e8fd93dbA3b25BC3495}, {name:collection, type:address, order:4, indexed:false, value:0x34d85c9CDeB23FA97cb08333b511ac86E1C4E258, valueString:0x34d85c9CDeB23FA97cb08333b511ac86E1C4E258}, {name:tokenId, type:uint256, order:5, indexed:false, value:98253, valueString:98253}, {name:amount, type:uint256, order:6, indexed:false, value:1, valueString:1}, {name:paymentToken, type:address, order:7, indexed:false, value:0x0000000000000000000000000000000000000000, valueString:0x0000000000000000000000000000000000000000}, {name:price, type:uint256, order:8, indexed:false, value:1770000000000000000, valueString:1770000000000000000}, {name:listingTime, type:uint256, order:9, indexed:false, value:1676435710, valueString:1676435710}, {name:expirationTime, type:uint256, order:10, indexed:false, value:1676694910, valueString:1676694910}, {name:fees, type:tuple[], order:11, indexed:false}, {name:salt, type:uint256, order:12, indexed:false, value:306407767383169205770376005618740508580, valueString:306407767383169205770376005618740508580}, {name:extraParams, type:bytes, order:13, indexed:false, value:0x01, valueString:0x01}]}, {name:v, type:uint8, order:2, indexed:false, value:28, valueString:28}, {name:r, type:bytes32, order:3, indexed:false, value:DA207C2C248A134371F7D428A1B09622921CB3D96C2A39B3CB8B696F1D9BB9B2, valueString:DA207C2C248A134371F7D428A1B09622921CB3D96C2A39B3CB8B696F1D9BB9B2}, {name:s, type:bytes32, order:4, indexed:false, value:4B8749B41EFBF0A2517BA62B1F127D985C52C9BDB306A1290C48F100A8A8C73F, valueString:4B8749B41EFBF0A2517BA62B1F127D985C52C9BDB306A1290C48F100A8A8C73F}, {name:extraSignature, type:bytes, order:5, indexed:false, value:0x000000000000000000000000000000000000000000000000000000000000001BD1807929178BAFFD654361CC5AFBEF74E059D85FEA0A40464D6979232760BE8E02A3C6E5528D7149EF57FA004685AE41A84B0C473781F0B0EBB7198A1054346B, valueString:0x000000000000000000000000000000000000000000000000000000000000001BD1807929178BAFFD654361CC5AFBEF74E059D85FEA0A40464D6979232760BE8E02A3C6E5528D7149EF57FA004685AE41A84B0C473781F0B0EBB7198A1054346B}, {name:signatureVersion, type:uint8, order:6, indexed:false, value:0, valueString:0}, {name:blockNumber, type:uint256, order:7, indexed:false, value:16632259, valueString:16632259}], buy=[{name:order, type:tuple, order:1, indexed:false, value:[{name:trader, type:address, order:1, indexed:false, value:0xA43d1D06eD27632f94be1337216A414c9B515dfA, valueString:0xA43d1D06eD27632f94be1337216A414c9B515dfA}, {name:side, type:uint8, order:2, indexed:false, value:0, valueString:0}, {name:matchingPolicy, type:address, order:3, indexed:false, value:0x0000000000daB4A563819e8fd93dbA3b25BC3495, valueString:0x0000000000daB4A563819e8fd93dbA3b25BC3495}, {name:collection, type:address, order:4, indexed:false, value:0x34d85c9CDeB23FA97cb08333b511ac86E1C4E258, valueString:0x34d85c9CDeB23FA97cb08333b511ac86E1C4E258}, {name:tokenId, type:uint256, order:5, indexed:false, value:98253, valueString:98253}, {name:amount, type:uint256, order:6, indexed:false, value:1, valueString:1}, {name:paymentToken, type:address, order:7, indexed:false, value:0x0000000000000000000000000000000000000000, valueString:0x0000000000000000000000000000000000000000}, {name:price, type:uint256, order:8, indexed:false, value:1770000000000000000, valueString:1770000000000000000}, {name:listingTime, type:uint256, order:9, indexed:false, value:1676435711, valueString:1676435711}, {name:expirationTime, type:uint256, order:10, indexed:false, value:1676444927, valueString:1676444927}, {name:fees, type:tuple[], order:11, indexed:false}, {name:salt, type:uint256, order:12, indexed:false, value:200968501994840907986523658000406779454, valueString:200968501994840907986523658000406779454}, {name:extraParams, type:bytes, order:13, indexed:false, value:0x01, valueString:0x01}], valueString:[{name:trader, type:address, order:1, indexed:false, value:0xA43d1D06eD27632f94be1337216A414c9B515dfA, valueString:0xA43d1D06eD27632f94be1337216A414c9B515dfA}, {name:side, type:uint8, order:2, indexed:false, value:0, valueString:0}, {name:matchingPolicy, type:address, order:3, indexed:false, value:0x0000000000daB4A563819e8fd93dbA3b25BC3495, valueString:0x0000000000daB4A563819e8fd93dbA3b25BC3495}, {name:collection, type:address, order:4, indexed:false, value:0x34d85c9CDeB23FA97cb08333b511ac86E1C4E258, valueString:0x34d85c9CDeB23FA97cb08333b511ac86E1C4E258}, {name:tokenId, type:uint256, order:5, indexed:false, value:98253, valueString:98253}, {name:amount, type:uint256, order:6, indexed:false, value:1, valueString:1}, {name:paymentToken, type:address, order:7, indexed:false, value:0x0000000000000000000000000000000000000000, valueString:0x0000000000000000000000000000000000000000}, {name:price, type:uint256, order:8, indexed:false, value:1770000000000000000, valueString:1770000000000000000}, {name:listingTime, type:uint256, order:9, indexed:false, value:1676435711, valueString:1676435711}, {name:expirationTime, type:uint256, order:10, indexed:false, value:1676444927, valueString:1676444927}, {name:fees, type:tuple[], order:11, indexed:false}, {name:salt, type:uint256, order:12, indexed:false, value:200968501994840907986523658000406779454, valueString:200968501994840907986523658000406779454}, {name:extraParams, type:bytes, order:13, indexed:false, value:0x01, valueString:0x01}]}, {name:v, type:uint8, order:2, indexed:false, value:0, valueString:0}, {name:r, type:bytes32, order:3, indexed:false, value:0000000000000000000000000000000000000000000000000000000000000000, valueString:0000000000000000000000000000000000000000000000000000000000000000}, {name:s, type:bytes32, order:4, indexed:false, value:0000000000000000000000000000000000000000000000000000000000000000, valueString:0000000000000000000000000000000000000000000000000000000000000000}, {name:extraSignature, type:bytes, order:5, indexed:false, value:0x000000000000000000000000000000000000000000000000000000000000001B0B7162ED0DB2E873DCCF9649309E798200635F08C532C7524F479486A09B76214E18C4672722C38F7744447E0518F23F65CCA30C75D107F2CEA0FBC5DD0880EE, valueString:0x000000000000000000000000000000000000000000000000000000000000001B0B7162ED0DB2E873DCCF9649309E798200635F08C532C7524F479486A09B76214E18C4672722C38F7744447E0518F23F65CCA30C75D107F2CEA0FBC5DD0880EE}, {name:signatureVersion, type:uint8, order:6, indexed:false, value:0, valueString:0}, {name:blockNumber, type:uint256, order:7, indexed:false, value:16632259, valueString:16632259}] )
    • Null: 0x000...001.62881deb( )
    • Null: 0x000...001.32e4bd3b( )
    • Null: 0x000...001.6e89438b( )
    • PolicyManager.isPolicyWhitelisted( policy=0x0000000000daB4A563819e8fd93dbA3b25BC3495 ) => ( True )
    • StandardPolicyERC721.canMatchMakerAsk( makerAsk=[{name:trader, type:address, order:1, indexed:false, value:0xb7737576929aFd9445fcE22bcE9F929779896dA9, valueString:0xb7737576929aFd9445fcE22bcE9F929779896dA9}, {name:side, type:uint8, order:2, indexed:false, value:1, valueString:1}, {name:matchingPolicy, type:address, order:3, indexed:false, value:0x0000000000daB4A563819e8fd93dbA3b25BC3495, valueString:0x0000000000daB4A563819e8fd93dbA3b25BC3495}, {name:collection, type:address, order:4, indexed:false, value:0x34d85c9CDeB23FA97cb08333b511ac86E1C4E258, valueString:0x34d85c9CDeB23FA97cb08333b511ac86E1C4E258}, {name:tokenId, type:uint256, order:5, indexed:false, value:98253, valueString:98253}, {name:amount, type:uint256, order:6, indexed:false, value:1, valueString:1}, {name:paymentToken, type:address, order:7, indexed:false, value:0x0000000000000000000000000000000000000000, valueString:0x0000000000000000000000000000000000000000}, {name:price, type:uint256, order:8, indexed:false, value:1770000000000000000, valueString:1770000000000000000}, {name:listingTime, type:uint256, order:9, indexed:false, value:1676435710, valueString:1676435710}, {name:expirationTime, type:uint256, order:10, indexed:false, value:1676694910, valueString:1676694910}, {name:fees, type:tuple[], order:11, indexed:false}, {name:salt, type:uint256, order:12, indexed:false, value:306407767383169205770376005618740508580, valueString:306407767383169205770376005618740508580}, {name:extraParams, type:bytes, order:13, indexed:false, value:0x01, valueString:0x01}], takerBid=[{name:trader, type:address, order:1, indexed:false, value:0xA43d1D06eD27632f94be1337216A414c9B515dfA, valueString:0xA43d1D06eD27632f94be1337216A414c9B515dfA}, {name:side, type:uint8, order:2, indexed:false, value:0, valueString:0}, {name:matchingPolicy, type:address, order:3, indexed:false, value:0x0000000000daB4A563819e8fd93dbA3b25BC3495, valueString:0x0000000000daB4A563819e8fd93dbA3b25BC3495}, {name:collection, type:address, order:4, indexed:false, value:0x34d85c9CDeB23FA97cb08333b511ac86E1C4E258, valueString:0x34d85c9CDeB23FA97cb08333b511ac86E1C4E258}, {name:tokenId, type:uint256, order:5, indexed:false, value:98253, valueString:98253}, {name:amount, type:uint256, order:6, indexed:false, value:1, valueString:1}, {name:paymentToken, type:address, order:7, indexed:false, value:0x0000000000000000000000000000000000000000, valueString:0x0000000000000000000000000000000000000000}, {name:price, type:uint256, order:8, indexed:false, value:1770000000000000000, valueString:1770000000000000000}, {name:listingTime, type:uint256, order:9, indexed:false, value:1676435711, valueString:1676435711}, {name:expirationTime, type:uint256, order:10, indexed:false, value:1676444927, valueString:1676444927}, {name:fees, type:tuple[], order:11, indexed:false}, {name:salt, type:uint256, order:12, indexed:false, value:200968501994840907986523658000406779454, valueString:200968501994840907986523658000406779454}, {name:extraParams, type:bytes, order:13, indexed:false, value:0x01, valueString:0x01}] ) => ( True, 1770000000000000000, 98253, 1, 0 )
    • ETH 0.00885 GnosisSafeProxy.CALL( )
      • ETH 0.00885 GnosisSafe.DELEGATECALL( )
      • ETH 1.76115 0xb7737576929afd9445fce22bce9f929779896da9.CALL( )
      • ExecutionDelegate.transferERC721( collection=0x34d85c9CDeB23FA97cb08333b511ac86E1C4E258, from=0xb7737576929aFd9445fcE22bcE9F929779896dA9, to=0xA43d1D06eD27632f94be1337216A414c9B515dfA, tokenId=98253 )
        • Land.safeTransferFrom( from=0xb7737576929aFd9445fcE22bcE9F929779896dA9, to=0xA43d1D06eD27632f94be1337216A414c9B515dfA, tokenId=98253 )
          execute[BlurExchange (ln:118)]
          File 1 of 8: ERC1967Proxy
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts v4.4.1 (proxy/ERC1967/ERC1967Proxy.sol)
          pragma solidity 0.8.17;
          // OpenZeppelin Contracts v4.4.1 (proxy/Proxy.sol)
          /**
           * @dev This abstract contract provides a fallback function that delegates all calls to another contract using the EVM
           * instruction `delegatecall`. We refer to the second contract as the _implementation_ behind the proxy, and it has to
           * be specified by overriding the virtual {_implementation} function.
           *
           * Additionally, delegation to the implementation can be triggered manually through the {_fallback} function, or to a
           * different contract through the {_delegate} function.
           *
           * The success and return data of the delegated call will be returned back to the caller of the proxy.
           */
          abstract contract Proxy {
              /**
               * @dev Delegates the current call to `implementation`.
               *
               * This function does not return to its internall call site, it will return directly to the external caller.
               */
              function _delegate(address implementation) internal virtual {
                  assembly {
                      // Copy msg.data. We take full control of memory in this inline assembly
                      // block because it will not return to Solidity code. We overwrite the
                      // Solidity scratch pad at memory position 0.
                      calldatacopy(0, 0, calldatasize())
                      // Call the implementation.
                      // out and outsize are 0 because we don't know the size yet.
                      let result := delegatecall(gas(), implementation, 0, calldatasize(), 0, 0)
                      // Copy the returned data.
                      returndatacopy(0, 0, returndatasize())
                      switch result
                      // delegatecall returns 0 on error.
                      case 0 {
                          revert(0, returndatasize())
                      }
                      default {
                          return(0, returndatasize())
                      }
                  }
              }
              /**
               * @dev This is a virtual function that should be overriden so it returns the address to which the fallback function
               * and {_fallback} should delegate.
               */
              function _implementation() internal view virtual returns (address);
              /**
               * @dev Delegates the current call to the address returned by `_implementation()`.
               *
               * This function does not return to its internall call site, it will return directly to the external caller.
               */
              function _fallback() internal virtual {
                  _beforeFallback();
                  _delegate(_implementation());
              }
              /**
               * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if no other
               * function in the contract matches the call data.
               */
              fallback() external payable virtual {
                  _fallback();
              }
              /**
               * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if call data
               * is empty.
               */
              receive() external payable virtual {
                  _fallback();
              }
              /**
               * @dev Hook that is called before falling back to the implementation. Can happen as part of a manual `_fallback`
               * call, or as part of the Solidity `fallback` or `receive` functions.
               *
               * If overriden should call `super._beforeFallback()`.
               */
              function _beforeFallback() internal virtual {}
          }
          // OpenZeppelin Contracts v4.4.1 (proxy/ERC1967/ERC1967Upgrade.sol)
          /**
           * @dev This abstract contract provides getters and event emitting update functions for
           * https://eips.ethereum.org/EIPS/eip-1967[EIP1967] slots.
           *
           * _Available since v4.1._
           *
           * @custom:oz-upgrades-unsafe-allow delegatecall
           */
          abstract contract ERC1967Upgrade {
              // This is the keccak-256 hash of "eip1967.proxy.rollback" subtracted by 1
              bytes32 private constant _ROLLBACK_SLOT = 0x4910fdfa16fed3260ed0e7147f7cc6da11a60208b5b9406d12a635614ffd9143;
              /**
               * @dev Storage slot with the address of the current implementation.
               * This is the keccak-256 hash of "eip1967.proxy.implementation" subtracted by 1, and is
               * validated in the constructor.
               */
              bytes32 internal constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;
              /**
               * @dev Emitted when the implementation is upgraded.
               */
              event Upgraded(address indexed implementation);
              /**
               * @dev Returns the current implementation address.
               */
              function _getImplementation() internal view returns (address) {
                  return StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value;
              }
              /**
               * @dev Stores a new address in the EIP1967 implementation slot.
               */
              function _setImplementation(address newImplementation) private {
                  require(Address.isContract(newImplementation), "ERC1967: new implementation is not a contract");
                  StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value = newImplementation;
              }
              /**
               * @dev Perform implementation upgrade
               *
               * Emits an {Upgraded} event.
               */
              function _upgradeTo(address newImplementation) internal {
                  _setImplementation(newImplementation);
                  emit Upgraded(newImplementation);
              }
              /**
               * @dev Perform implementation upgrade with additional setup call.
               *
               * Emits an {Upgraded} event.
               */
              function _upgradeToAndCall(
                  address newImplementation,
                  bytes memory data,
                  bool forceCall
              ) internal {
                  _upgradeTo(newImplementation);
                  if (data.length > 0 || forceCall) {
                      Address.functionDelegateCall(newImplementation, data);
                  }
              }
              /**
               * @dev Perform implementation upgrade with security checks for UUPS proxies, and additional setup call.
               *
               * Emits an {Upgraded} event.
               */
              function _upgradeToAndCallSecure(
                  address newImplementation,
                  bytes memory data,
                  bool forceCall
              ) internal {
                  address oldImplementation = _getImplementation();
                  // Initial upgrade and setup call
                  _setImplementation(newImplementation);
                  if (data.length > 0 || forceCall) {
                      Address.functionDelegateCall(newImplementation, data);
                  }
                  // Perform rollback test if not already in progress
                  StorageSlot.BooleanSlot storage rollbackTesting = StorageSlot.getBooleanSlot(_ROLLBACK_SLOT);
                  if (!rollbackTesting.value) {
                      // Trigger rollback using upgradeTo from the new implementation
                      rollbackTesting.value = true;
                      Address.functionDelegateCall(
                          newImplementation,
                          abi.encodeWithSignature("upgradeTo(address)", oldImplementation)
                      );
                      rollbackTesting.value = false;
                      // Check rollback was effective
                      require(oldImplementation == _getImplementation(), "ERC1967Upgrade: upgrade breaks further upgrades");
                      // Finally reset to the new implementation and log the upgrade
                      _upgradeTo(newImplementation);
                  }
              }
              /**
               * @dev Storage slot with the admin of the contract.
               * This is the keccak-256 hash of "eip1967.proxy.admin" subtracted by 1, and is
               * validated in the constructor.
               */
              bytes32 internal constant _ADMIN_SLOT = 0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103;
              /**
               * @dev Emitted when the admin account has changed.
               */
              event AdminChanged(address previousAdmin, address newAdmin);
              /**
               * @dev Returns the current admin.
               */
              function _getAdmin() internal view returns (address) {
                  return StorageSlot.getAddressSlot(_ADMIN_SLOT).value;
              }
              /**
               * @dev Stores a new address in the EIP1967 admin slot.
               */
              function _setAdmin(address newAdmin) private {
                  require(newAdmin != address(0), "ERC1967: new admin is the zero address");
                  StorageSlot.getAddressSlot(_ADMIN_SLOT).value = newAdmin;
              }
              /**
               * @dev Changes the admin of the proxy.
               *
               * Emits an {AdminChanged} event.
               */
              function _changeAdmin(address newAdmin) internal {
                  emit AdminChanged(_getAdmin(), newAdmin);
                  _setAdmin(newAdmin);
              }
              /**
               * @dev The storage slot of the UpgradeableBeacon contract which defines the implementation for this proxy.
               * This is bytes32(uint256(keccak256('eip1967.proxy.beacon')) - 1)) and is validated in the constructor.
               */
              bytes32 internal constant _BEACON_SLOT = 0xa3f0ad74e5423aebfd80d3ef4346578335a9a72aeaee59ff6cb3582b35133d50;
              /**
               * @dev Emitted when the beacon is upgraded.
               */
              event BeaconUpgraded(address indexed beacon);
              /**
               * @dev Returns the current beacon.
               */
              function _getBeacon() internal view returns (address) {
                  return StorageSlot.getAddressSlot(_BEACON_SLOT).value;
              }
              /**
               * @dev Stores a new beacon in the EIP1967 beacon slot.
               */
              function _setBeacon(address newBeacon) private {
                  require(Address.isContract(newBeacon), "ERC1967: new beacon is not a contract");
                  require(
                      Address.isContract(IBeacon(newBeacon).implementation()),
                      "ERC1967: beacon implementation is not a contract"
                  );
                  StorageSlot.getAddressSlot(_BEACON_SLOT).value = newBeacon;
              }
              /**
               * @dev Perform beacon upgrade with additional setup call. Note: This upgrades the address of the beacon, it does
               * not upgrade the implementation contained in the beacon (see {UpgradeableBeacon-_setImplementation} for that).
               *
               * Emits a {BeaconUpgraded} event.
               */
              function _upgradeBeaconToAndCall(
                  address newBeacon,
                  bytes memory data,
                  bool forceCall
              ) internal {
                  _setBeacon(newBeacon);
                  emit BeaconUpgraded(newBeacon);
                  if (data.length > 0 || forceCall) {
                      Address.functionDelegateCall(IBeacon(newBeacon).implementation(), data);
                  }
              }
          }
          /**
           * @dev This contract implements an upgradeable proxy. It is upgradeable because calls are delegated to an
           * implementation address that can be changed. This address is stored in storage in the location specified by
           * https://eips.ethereum.org/EIPS/eip-1967[EIP1967], so that it doesn't conflict with the storage layout of the
           * implementation behind the proxy.
           */
          contract ERC1967Proxy is Proxy, ERC1967Upgrade {
              /**
               * @dev Initializes the upgradeable proxy with an initial implementation specified by `_logic`.
               *
               * If `_data` is nonempty, it's used as data in a delegate call to `_logic`. This will typically be an encoded
               * function call, and allows initializating the storage of the proxy like a Solidity constructor.
               */
              constructor(address _logic, bytes memory _data) payable {
                  assert(_IMPLEMENTATION_SLOT == bytes32(uint256(keccak256("eip1967.proxy.implementation")) - 1));
                  _upgradeToAndCall(_logic, _data, false);
              }
              /**
               * @dev Returns the current implementation address.
               */
              function _implementation() internal view virtual override returns (address impl) {
                  return ERC1967Upgrade._getImplementation();
              }
          }
          // OpenZeppelin Contracts v4.4.1 (proxy/beacon/IBeacon.sol)
          /**
           * @dev This is the interface that {BeaconProxy} expects of its beacon.
           */
          interface IBeacon {
              /**
               * @dev Must return an address that can be used as a delegate call target.
               *
               * {BeaconProxy} will check that this address is a contract.
               */
              function implementation() external view returns (address);
          }
          // OpenZeppelin Contracts v4.4.1 (utils/Address.sol)
          pragma solidity ^0.8.0;
          /**
           * @dev Collection of functions related to the address type
           */
          library Address {
              /**
               * @dev Returns true if `account` is a contract.
               *
               * [IMPORTANT]
               * ====
               * It is unsafe to assume that an address for which this function returns
               * false is an externally-owned account (EOA) and not a contract.
               *
               * Among others, `isContract` will return false for the following
               * types of addresses:
               *
               *  - an externally-owned account
               *  - a contract in construction
               *  - an address where a contract will be created
               *  - an address where a contract lived, but was destroyed
               * ====
               */
              function isContract(address account) internal view returns (bool) {
                  // This method relies on extcodesize, which returns 0 for contracts in
                  // construction, since the code is only stored at the end of the
                  // constructor execution.
                  uint256 size;
                  assembly {
                      size := extcodesize(account)
                  }
                  return size > 0;
              }
              /**
               * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
               * `recipient`, forwarding all available gas and reverting on errors.
               *
               * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
               * of certain opcodes, possibly making contracts go over the 2300 gas limit
               * imposed by `transfer`, making them unable to receive funds via
               * `transfer`. {sendValue} removes this limitation.
               *
               * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
               *
               * IMPORTANT: because control is transferred to `recipient`, care must be
               * taken to not create reentrancy vulnerabilities. Consider using
               * {ReentrancyGuard} or the
               * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
               */
              function sendValue(address payable recipient, uint256 amount) internal {
                  require(address(this).balance >= amount, "Address: insufficient balance");
                  (bool success, ) = recipient.call{value: amount}("");
                  require(success, "Address: unable to send value, recipient may have reverted");
              }
              /**
               * @dev Performs a Solidity function call using a low level `call`. A
               * plain `call` is an unsafe replacement for a function call: use this
               * function instead.
               *
               * If `target` reverts with a revert reason, it is bubbled up by this
               * function (like regular Solidity function calls).
               *
               * Returns the raw returned data. To convert to the expected return value,
               * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
               *
               * Requirements:
               *
               * - `target` must be a contract.
               * - calling `target` with `data` must not revert.
               *
               * _Available since v3.1._
               */
              function functionCall(address target, bytes memory data) internal returns (bytes memory) {
                  return functionCall(target, data, "Address: low-level call failed");
              }
              /**
               * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
               * `errorMessage` as a fallback revert reason when `target` reverts.
               *
               * _Available since v3.1._
               */
              function functionCall(
                  address target,
                  bytes memory data,
                  string memory errorMessage
              ) internal returns (bytes memory) {
                  return functionCallWithValue(target, data, 0, errorMessage);
              }
              /**
               * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
               * but also transferring `value` wei to `target`.
               *
               * Requirements:
               *
               * - the calling contract must have an ETH balance of at least `value`.
               * - the called Solidity function must be `payable`.
               *
               * _Available since v3.1._
               */
              function functionCallWithValue(
                  address target,
                  bytes memory data,
                  uint256 value
              ) internal returns (bytes memory) {
                  return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
              }
              /**
               * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
               * with `errorMessage` as a fallback revert reason when `target` reverts.
               *
               * _Available since v3.1._
               */
              function functionCallWithValue(
                  address target,
                  bytes memory data,
                  uint256 value,
                  string memory errorMessage
              ) internal returns (bytes memory) {
                  require(address(this).balance >= value, "Address: insufficient balance for call");
                  require(isContract(target), "Address: call to non-contract");
                  (bool success, bytes memory returndata) = target.call{value: value}(data);
                  return verifyCallResult(success, returndata, errorMessage);
              }
              /**
               * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
               * but performing a static call.
               *
               * _Available since v3.3._
               */
              function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
                  return functionStaticCall(target, data, "Address: low-level static call failed");
              }
              /**
               * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
               * but performing a static call.
               *
               * _Available since v3.3._
               */
              function functionStaticCall(
                  address target,
                  bytes memory data,
                  string memory errorMessage
              ) internal view returns (bytes memory) {
                  require(isContract(target), "Address: static call to non-contract");
                  (bool success, bytes memory returndata) = target.staticcall(data);
                  return verifyCallResult(success, returndata, errorMessage);
              }
              /**
               * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
               * but performing a delegate call.
               *
               * _Available since v3.4._
               */
              function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
                  return functionDelegateCall(target, data, "Address: low-level delegate call failed");
              }
              /**
               * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
               * but performing a delegate call.
               *
               * _Available since v3.4._
               */
              function functionDelegateCall(
                  address target,
                  bytes memory data,
                  string memory errorMessage
              ) internal returns (bytes memory) {
                  require(isContract(target), "Address: delegate call to non-contract");
                  (bool success, bytes memory returndata) = target.delegatecall(data);
                  return verifyCallResult(success, returndata, errorMessage);
              }
              /**
               * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
               * revert reason using the provided one.
               *
               * _Available since v4.3._
               */
              function verifyCallResult(
                  bool success,
                  bytes memory returndata,
                  string memory errorMessage
              ) internal pure returns (bytes memory) {
                  if (success) {
                      return returndata;
                  } else {
                      // Look for revert reason and bubble it up if present
                      if (returndata.length > 0) {
                          // The easiest way to bubble the revert reason is using memory via assembly
                          assembly {
                              let returndata_size := mload(returndata)
                              revert(add(32, returndata), returndata_size)
                          }
                      } else {
                          revert(errorMessage);
                      }
                  }
              }
          }
          // OpenZeppelin Contracts v4.4.1 (utils/StorageSlot.sol)
          /**
           * @dev Library for reading and writing primitive types to specific storage slots.
           *
           * Storage slots are often used to avoid storage conflict when dealing with upgradeable contracts.
           * This library helps with reading and writing to such slots without the need for inline assembly.
           *
           * The functions in this library return Slot structs that contain a `value` member that can be used to read or write.
           *
           * Example usage to set ERC1967 implementation slot:
           * ```
           * contract ERC1967 {
           *     bytes32 internal constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;
           *
           *     function _getImplementation() internal view returns (address) {
           *         return StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value;
           *     }
           *
           *     function _setImplementation(address newImplementation) internal {
           *         require(Address.isContract(newImplementation), "ERC1967: new implementation is not a contract");
           *         StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value = newImplementation;
           *     }
           * }
           * ```
           *
           * _Available since v4.1 for `address`, `bool`, `bytes32`, and `uint256`._
           */
          library StorageSlot {
              struct AddressSlot {
                  address value;
              }
              struct BooleanSlot {
                  bool value;
              }
              struct Bytes32Slot {
                  bytes32 value;
              }
              struct Uint256Slot {
                  uint256 value;
              }
              /**
               * @dev Returns an `AddressSlot` with member `value` located at `slot`.
               */
              function getAddressSlot(bytes32 slot) internal pure returns (AddressSlot storage r) {
                  assembly {
                      r.slot := slot
                  }
              }
              /**
               * @dev Returns an `BooleanSlot` with member `value` located at `slot`.
               */
              function getBooleanSlot(bytes32 slot) internal pure returns (BooleanSlot storage r) {
                  assembly {
                      r.slot := slot
                  }
              }
              /**
               * @dev Returns an `Bytes32Slot` with member `value` located at `slot`.
               */
              function getBytes32Slot(bytes32 slot) internal pure returns (Bytes32Slot storage r) {
                  assembly {
                      r.slot := slot
                  }
              }
              /**
               * @dev Returns an `Uint256Slot` with member `value` located at `slot`.
               */
              function getUint256Slot(bytes32 slot) internal pure returns (Uint256Slot storage r) {
                  assembly {
                      r.slot := slot
                  }
              }
          }

          File 2 of 8: GnosisSafeProxy
          // SPDX-License-Identifier: LGPL-3.0-only
          pragma solidity >=0.7.0 <0.9.0;
          
          /// @title IProxy - Helper interface to access masterCopy of the Proxy on-chain
          /// @author Richard Meissner - <[email protected]>
          interface IProxy {
              function masterCopy() external view returns (address);
          }
          
          /// @title GnosisSafeProxy - Generic proxy contract allows to execute all transactions applying the code of a master contract.
          /// @author Stefan George - <[email protected]>
          /// @author Richard Meissner - <[email protected]>
          contract GnosisSafeProxy {
              // singleton always needs to be first declared variable, to ensure that it is at the same location in the contracts to which calls are delegated.
              // To reduce deployment costs this variable is internal and needs to be retrieved via `getStorageAt`
              address internal singleton;
          
              /// @dev Constructor function sets address of singleton contract.
              /// @param _singleton Singleton address.
              constructor(address _singleton) {
                  require(_singleton != address(0), "Invalid singleton address provided");
                  singleton = _singleton;
              }
          
              /// @dev Fallback function forwards all transactions and returns all received return data.
              fallback() external payable {
                  // solhint-disable-next-line no-inline-assembly
                  assembly {
                      let _singleton := and(sload(0), 0xffffffffffffffffffffffffffffffffffffffff)
                      // 0xa619486e == keccak("masterCopy()"). The value is right padded to 32-bytes with 0s
                      if eq(calldataload(0), 0xa619486e00000000000000000000000000000000000000000000000000000000) {
                          mstore(0, _singleton)
                          return(0, 0x20)
                      }
                      calldatacopy(0, 0, calldatasize())
                      let success := delegatecall(gas(), _singleton, 0, calldatasize(), 0, 0)
                      returndatacopy(0, 0, returndatasize())
                      if eq(success, 0) {
                          revert(0, returndatasize())
                      }
                      return(0, returndatasize())
                  }
              }
          }
          
          /// @title Proxy Factory - Allows to create new proxy contact and execute a message call to the new proxy within one transaction.
          /// @author Stefan George - <[email protected]>
          contract GnosisSafeProxyFactory {
              event ProxyCreation(GnosisSafeProxy proxy, address singleton);
          
              /// @dev Allows to create new proxy contact and execute a message call to the new proxy within one transaction.
              /// @param singleton Address of singleton contract.
              /// @param data Payload for message call sent to new proxy contract.
              function createProxy(address singleton, bytes memory data) public returns (GnosisSafeProxy proxy) {
                  proxy = new GnosisSafeProxy(singleton);
                  if (data.length > 0)
                      // solhint-disable-next-line no-inline-assembly
                      assembly {
                          if eq(call(gas(), proxy, 0, add(data, 0x20), mload(data), 0, 0), 0) {
                              revert(0, 0)
                          }
                      }
                  emit ProxyCreation(proxy, singleton);
              }
          
              /// @dev Allows to retrieve the runtime code of a deployed Proxy. This can be used to check that the expected Proxy was deployed.
              function proxyRuntimeCode() public pure returns (bytes memory) {
                  return type(GnosisSafeProxy).runtimeCode;
              }
          
              /// @dev Allows to retrieve the creation code used for the Proxy deployment. With this it is easily possible to calculate predicted address.
              function proxyCreationCode() public pure returns (bytes memory) {
                  return type(GnosisSafeProxy).creationCode;
              }
          
              /// @dev Allows to create new proxy contact using CREATE2 but it doesn't run the initializer.
              ///      This method is only meant as an utility to be called from other methods
              /// @param _singleton Address of singleton contract.
              /// @param initializer Payload for message call sent to new proxy contract.
              /// @param saltNonce Nonce that will be used to generate the salt to calculate the address of the new proxy contract.
              function deployProxyWithNonce(
                  address _singleton,
                  bytes memory initializer,
                  uint256 saltNonce
              ) internal returns (GnosisSafeProxy proxy) {
                  // If the initializer changes the proxy address should change too. Hashing the initializer data is cheaper than just concatinating it
                  bytes32 salt = keccak256(abi.encodePacked(keccak256(initializer), saltNonce));
                  bytes memory deploymentData = abi.encodePacked(type(GnosisSafeProxy).creationCode, uint256(uint160(_singleton)));
                  // solhint-disable-next-line no-inline-assembly
                  assembly {
                      proxy := create2(0x0, add(0x20, deploymentData), mload(deploymentData), salt)
                  }
                  require(address(proxy) != address(0), "Create2 call failed");
              }
          
              /// @dev Allows to create new proxy contact and execute a message call to the new proxy within one transaction.
              /// @param _singleton Address of singleton contract.
              /// @param initializer Payload for message call sent to new proxy contract.
              /// @param saltNonce Nonce that will be used to generate the salt to calculate the address of the new proxy contract.
              function createProxyWithNonce(
                  address _singleton,
                  bytes memory initializer,
                  uint256 saltNonce
              ) public returns (GnosisSafeProxy proxy) {
                  proxy = deployProxyWithNonce(_singleton, initializer, saltNonce);
                  if (initializer.length > 0)
                      // solhint-disable-next-line no-inline-assembly
                      assembly {
                          if eq(call(gas(), proxy, 0, add(initializer, 0x20), mload(initializer), 0, 0), 0) {
                              revert(0, 0)
                          }
                      }
                  emit ProxyCreation(proxy, _singleton);
              }
          
              /// @dev Allows to create new proxy contact, execute a message call to the new proxy and call a specified callback within one transaction
              /// @param _singleton Address of singleton contract.
              /// @param initializer Payload for message call sent to new proxy contract.
              /// @param saltNonce Nonce that will be used to generate the salt to calculate the address of the new proxy contract.
              /// @param callback Callback that will be invoced after the new proxy contract has been successfully deployed and initialized.
              function createProxyWithCallback(
                  address _singleton,
                  bytes memory initializer,
                  uint256 saltNonce,
                  IProxyCreationCallback callback
              ) public returns (GnosisSafeProxy proxy) {
                  uint256 saltNonceWithCallback = uint256(keccak256(abi.encodePacked(saltNonce, callback)));
                  proxy = createProxyWithNonce(_singleton, initializer, saltNonceWithCallback);
                  if (address(callback) != address(0)) callback.proxyCreated(proxy, _singleton, initializer, saltNonce);
              }
          
              /// @dev Allows to get the address for a new proxy contact created via `createProxyWithNonce`
              ///      This method is only meant for address calculation purpose when you use an initializer that would revert,
              ///      therefore the response is returned with a revert. When calling this method set `from` to the address of the proxy factory.
              /// @param _singleton Address of singleton contract.
              /// @param initializer Payload for message call sent to new proxy contract.
              /// @param saltNonce Nonce that will be used to generate the salt to calculate the address of the new proxy contract.
              function calculateCreateProxyWithNonceAddress(
                  address _singleton,
                  bytes calldata initializer,
                  uint256 saltNonce
              ) external returns (GnosisSafeProxy proxy) {
                  proxy = deployProxyWithNonce(_singleton, initializer, saltNonce);
                  revert(string(abi.encodePacked(proxy)));
              }
          }
          
          interface IProxyCreationCallback {
              function proxyCreated(
                  GnosisSafeProxy proxy,
                  address _singleton,
                  bytes calldata initializer,
                  uint256 saltNonce
              ) external;
          }

          File 3 of 8: Land
          // SPDX-License-Identifier: MIT
          pragma solidity 0.8.10;
          import "@openzeppelin/contracts/token/ERC721/extensions/ERC721Enumerable.sol";
          import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
          import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
          import "@openzeppelin/contracts/access/Ownable.sol";
          import "@openzeppelin/contracts/security/ReentrancyGuard.sol";
          import "@chainlink/contracts/src/v0.8/VRFConsumerBase.sol";
          import "@openzeppelin/contracts/utils/cryptography/MerkleProof.sol";
          contract Land is ERC721Enumerable, Ownable, ReentrancyGuard, VRFConsumerBase {
              using SafeERC20 for IERC20;
              // attributes
              string private baseURI;
              address public operator;
              bool public publicSaleActive;
              uint256 public publicSaleStartTime;
              uint256 public publicSalePriceLoweringDuration;
              uint256 public publicSaleStartPrice;
              uint256 public publicSaleEndingPrice;
              uint256 public currentNumLandsMintedPublicSale;
              uint256 public mintIndexPublicSaleAndContributors;
              address public tokenContract;
              bool private isKycCheckRequired;
              bytes32 public kycMerkleRoot;
              uint256 public maxMintPerTx;
              uint256 public maxMintPerAddress;
              mapping(address => uint256) public mintedPerAddress;
              bool public claimableActive; 
              bool public adminClaimStarted;
              
              address public alphaContract; 
              mapping(uint256 => bool) public alphaClaimed;
              uint256 public alphaClaimedAmount;
              address public betaContract; 
              mapping(uint256 => bool) public betaClaimed;
              uint256 public betaClaimedAmount;
              uint256 public betaNftIdCurrent;
              bool public contributorsClaimActive;
              mapping(address => uint256) public contributors;
              uint256 public futureLandsNftIdCurrent;
              address public futureMinter;
              Metadata[] public metadataHashes;
              bytes32 public keyHash;
              uint256 public fee;
              uint256 public publicSaleAndContributorsOffset;
              uint256 public alphaOffset;
              uint256 public betaOffset;
              mapping(bytes32 => bool) public isRandomRequestForPublicSaleAndContributors;
              bool public publicSaleAndContributorsRandomnessRequested;
              bool public ownerClaimRandomnessRequested;
              
              // constants
              uint256 immutable public MAX_LANDS;
              uint256 immutable public MAX_LANDS_WITH_FUTURE;
              uint256 immutable public MAX_ALPHA_NFT_AMOUNT;
              uint256 immutable public MAX_BETA_NFT_AMOUNT;
              uint256 immutable public MAX_PUBLIC_SALE_AMOUNT;
              uint256 immutable public RESERVED_CONTRIBUTORS_AMOUNT;
              uint256 immutable public MAX_FUTURE_LANDS;
              uint256 constant public MAX_MINT_PER_BLOCK = 150;
              // structs
              struct LandAmount {
                  uint256 alpha;
                  uint256 beta;
                  uint256 publicSale;
                  uint256 future;
              }
              struct ContributorAmount {
                  address contributor;
                  uint256 amount;
              }
              struct Metadata {
                  bytes32 metadataHash;
                  bytes32 shuffledArrayHash;
                  uint256 startIndex;
                  uint256 endIndex;
              }
              struct ContractAddresses {
                  address alphaContract;
                  address betaContract;
                  address tokenContract;
              }
              // modifiers
              modifier whenPublicSaleActive() {
                  require(publicSaleActive, "Public sale is not active");
                  _;
              }
              modifier whenContributorsClaimActive() {
                  require(contributorsClaimActive, "Contributors Claim is not active");
                  _;
              }
              modifier whenClaimableActive() {
                  require(claimableActive && !adminClaimStarted, "Claimable state is not active");
                  _;
              }
              modifier checkMetadataRange(Metadata memory _landMetadata){
                  require(_landMetadata.endIndex < MAX_LANDS_WITH_FUTURE, "Range upper bound cannot exceed MAX_LANDS_WITH_FUTURE - 1");
                  _;
              }
              modifier onlyContributors(address _contributor){
                  require(contributors[_contributor] > 0, "Only contributors can call this method");
                  _;
              }
              modifier onlyOperator() {
                  require(operator == msg.sender , "Only operator can call this method");
                  _;
              }
              modifier onlyFutureMinter() {
                  require(futureMinter == msg.sender , "Only futureMinter can call this method");
                  _;
              }
              modifier checkFirstMetadataRange(uint256 index, uint256 startIndex, uint256 endIndex) {
                  if(index == 0){
                      require(startIndex == 0, "For first metadata range lower bound should be 0");
                      require(endIndex == MAX_LANDS - 1, "For first metadata range upper bound should be MAX_LANDS - 1");
                  }
                  _;
              }
              // events
              event LandPublicSaleStart(
                  uint256 indexed _saleDuration,
                  uint256 indexed _saleStartTime
              );
              event LandPublicSaleStop(
                  uint256 indexed _currentPrice,
                  uint256 indexed _timeElapsed
              );
              event ClaimableStateChanged(bool indexed claimableActive);
              event ContributorsClaimStart(uint256 _timestamp);
              event ContributorsClaimStop(uint256 _timestamp);
              event StartingIndexSetPublicSale(uint256 indexed _startingIndex);
              event StartingIndexSetAlphaBeta(uint256 indexed _alphaOffset, uint256 indexed _betaOffset);
              event PublicSaleMint(address indexed sender, uint256 indexed numLands, uint256 indexed mintPrice);
              constructor(string memory name, string memory symbol,
                  ContractAddresses memory addresses,
                  LandAmount memory amount,
                  ContributorAmount[] memory _contributors,
                  address _vrfCoordinator, address _linkTokenAddress,
                  bytes32 _vrfKeyHash, uint256 _vrfFee,
                  address _operator
              ) ERC721(name, symbol) VRFConsumerBase(_vrfCoordinator, _linkTokenAddress) {
                  alphaContract = addresses.alphaContract;
                  betaContract = addresses.betaContract;
                  tokenContract = addresses.tokenContract;
                  MAX_ALPHA_NFT_AMOUNT = amount.alpha;
                  MAX_BETA_NFT_AMOUNT = amount.beta;
                  MAX_PUBLIC_SALE_AMOUNT = amount.publicSale;
                  MAX_FUTURE_LANDS = amount.future;
                  betaNftIdCurrent = amount.alpha; //beta starts after alpha
                  mintIndexPublicSaleAndContributors = amount.alpha + amount.beta; //public sale starts after beta
                  uint256 tempSum;
                  for(uint256 i; i<_contributors.length; ++i){
                      contributors[_contributors[i].contributor] = _contributors[i].amount;
                      tempSum += _contributors[i].amount;
                  }
                  RESERVED_CONTRIBUTORS_AMOUNT = tempSum;
                  MAX_LANDS = amount.alpha + amount.beta + amount.publicSale + RESERVED_CONTRIBUTORS_AMOUNT;
                  MAX_LANDS_WITH_FUTURE = MAX_LANDS + amount.future;
                  futureLandsNftIdCurrent = MAX_LANDS; //future starts after public sale
                  keyHash  = _vrfKeyHash;
                  fee = _vrfFee;
                  operator = _operator;
              }
              function _baseURI() internal view override returns (string memory) {
                  return baseURI;
              }
              function setBaseURI(string memory uri) external onlyOperator {
                  baseURI = uri;
              }
              function setOperator(address _operator) external onlyOwner {
                  operator = _operator;
              }
              function setMaxMintPerTx(uint256 _maxMintPerTx) external onlyOperator {
                  maxMintPerTx = _maxMintPerTx;
              }
              function setMaxMintPerAddress(uint256 _maxMintPerAddress) external onlyOperator {
                  maxMintPerAddress = _maxMintPerAddress;
              }
              function setKycCheckRequired(bool _isKycCheckRequired) external onlyOperator {
                  isKycCheckRequired = _isKycCheckRequired;
              }
              function setKycMerkleRoot(bytes32 _kycMerkleRoot) external onlyOperator {
                  kycMerkleRoot = _kycMerkleRoot;
              }
              // Public Sale Methods
              function startPublicSale(
                  uint256 _publicSalePriceLoweringDuration, 
                  uint256 _publicSaleStartPrice, 
                  uint256 _publicSaleEndingPrice,
                  uint256 _maxMintPerTx,
                  uint256 _maxMintPerAddress,
                  bool _isKycCheckRequired
              ) external onlyOperator {
                  require(!publicSaleActive, "Public sale has already begun");
                  
                  publicSalePriceLoweringDuration = _publicSalePriceLoweringDuration;
                  publicSaleStartPrice = _publicSaleStartPrice;
                  publicSaleEndingPrice = _publicSaleEndingPrice;
                  publicSaleStartTime = block.timestamp;
                  publicSaleActive = true;
                  maxMintPerTx = _maxMintPerTx;
                  maxMintPerAddress = _maxMintPerAddress;
                  isKycCheckRequired = _isKycCheckRequired;
                  emit LandPublicSaleStart(publicSalePriceLoweringDuration, publicSaleStartTime);
              }
              function stopPublicSale() external onlyOperator whenPublicSaleActive {
                  emit LandPublicSaleStop(getMintPrice(), getElapsedSaleTime());
                  publicSaleActive = false;
              }
              function getElapsedSaleTime() private view returns (uint256) {
                  return publicSaleStartTime > 0 ? block.timestamp - publicSaleStartTime : 0;
              }
              function getMintPrice() public view whenPublicSaleActive returns (uint256) {
                  uint256 elapsed = getElapsedSaleTime();
                  uint256 price;
                  if(elapsed < publicSalePriceLoweringDuration) {
                      // Linear decreasing function
                      price =
                          publicSaleStartPrice -
                              ( ( publicSaleStartPrice - publicSaleEndingPrice ) * elapsed ) / publicSalePriceLoweringDuration ;
                  } else {
                      price = publicSaleEndingPrice;
                  }
                  return price;
              }
              function mintLands(uint256 numLands, bytes32[] calldata merkleProof) external whenPublicSaleActive nonReentrant {
                  require(numLands > 0, "Must mint at least one beta");
                  require(currentNumLandsMintedPublicSale + numLands <= MAX_PUBLIC_SALE_AMOUNT, "Minting would exceed max supply");
                  require(numLands <= maxMintPerTx, "numLands should not exceed maxMintPerTx");
                  require(numLands + mintedPerAddress[msg.sender] <= maxMintPerAddress, "sender address cannot mint more than maxMintPerAddress lands");
                  if(isKycCheckRequired) {
                      require(MerkleProof.verify(merkleProof, kycMerkleRoot, keccak256(abi.encodePacked(msg.sender))), "Sender address is not in KYC allowlist");
                  } else {
                      require(msg.sender == tx.origin, "Minting from smart contracts is disallowed");
                  }
               
                  uint256 mintPrice = getMintPrice();
                  IERC20(tokenContract).safeTransferFrom(msg.sender, address(this), mintPrice * numLands);
                  currentNumLandsMintedPublicSale += numLands;
                  mintedPerAddress[msg.sender] += numLands;
                  emit PublicSaleMint(msg.sender, numLands, mintPrice);
                  mintLandsCommon(numLands, msg.sender);
              }
              function mintLandsCommon(uint256 numLands, address recipient) private {
                  for (uint256 i; i < numLands; ++i) {
                      _safeMint(recipient, mintIndexPublicSaleAndContributors++);
                  }
              }
              function withdraw() external onlyOwner {
                  uint256 balance = address(this).balance;
                  if(balance > 0){
                      Address.sendValue(payable(owner()), balance);
                  }
                  balance = IERC20(tokenContract).balanceOf(address(this));
                  if(balance > 0){
                      IERC20(tokenContract).safeTransfer(owner(), balance);
                  }
              }
              // Alpha/Beta Claim Methods
              function flipClaimableState() external onlyOperator {
                  claimableActive = !claimableActive;
                  emit ClaimableStateChanged(claimableActive);
              }
              function nftOwnerClaimLand(uint256[] calldata alphaTokenIds, uint256[] calldata betaTokenIds) external whenClaimableActive {
                  require(alphaTokenIds.length > 0 || betaTokenIds.length > 0, "Should claim at least one land");
                  require(alphaTokenIds.length + betaTokenIds.length <= MAX_MINT_PER_BLOCK, "Input length should be <= MAX_MINT_PER_BLOCK");
                  alphaClaimLand(alphaTokenIds);
                  betaClaimLand(betaTokenIds);
              }
              function alphaClaimLand(uint256[] calldata alphaTokenIds) private {
                  for(uint256 i; i < alphaTokenIds.length; ++i){
                      uint256 alphaTokenId = alphaTokenIds[i];
                      require(!alphaClaimed[alphaTokenId], "ALPHA NFT already claimed");
                      require(ERC721(alphaContract).ownerOf(alphaTokenId) == msg.sender, "Must own all of the alpha defined by alphaTokenIds");
                      
                      alphaClaimLandByTokenId(alphaTokenId);    
                  }
              }
              function alphaClaimLandByTokenId(uint256 alphaTokenId) private {
                  alphaClaimed[alphaTokenId] = true;
                  ++alphaClaimedAmount;        
                  _safeMint(msg.sender, alphaTokenId);
              }
              function betaClaimLand(uint256[] calldata betaTokenIds) private {
                  for(uint256 i; i < betaTokenIds.length; ++i){
                      uint256 betaTokenId = betaTokenIds[i];
                      require(!betaClaimed[betaTokenId], "BETA NFT already claimed");
                      require(ERC721(betaContract).ownerOf(betaTokenId) == msg.sender, "Must own all of the beta defined by betaTokenIds");
                      
                      betaClaimLandByTokenId(betaTokenId);    
                  }
              }
              function betaClaimLandByTokenId(uint256 betaTokenId) private {
                  betaClaimed[betaTokenId] = true;
                  ++betaClaimedAmount;
                  _safeMint(msg.sender, betaNftIdCurrent++);
              }
              // Contributors Claim Methods
              function startContributorsClaimPeriod() onlyOperator external {
                  require(!contributorsClaimActive, "Contributors claim is already active");
                  contributorsClaimActive = true;
                  emit ContributorsClaimStart(block.timestamp);
              }
              function stopContributorsClaimPeriod() onlyOperator external whenContributorsClaimActive {
                  contributorsClaimActive = false;
                  emit ContributorsClaimStop(block.timestamp);
              }
              function contributorsClaimLand(uint256 amount, address recipient) external onlyContributors(msg.sender) whenContributorsClaimActive {
                  require(amount > 0, "Must mint at least one land");
                  require(amount <= MAX_MINT_PER_BLOCK, "amount should not exceed MAX_MINT_PER_BLOCK");
                  require(amount <= contributors[msg.sender], "Contributor cannot claim other lands");
                  contributors[msg.sender] -= amount;
                  mintLandsCommon(amount, recipient);
              }
              function claimUnclaimedAndUnsoldLands(address recipient) external onlyOwner {
                  claimUnclaimedAndUnsoldLandsWithAmount(recipient, MAX_MINT_PER_BLOCK);
              }
              function claimUnclaimedAndUnsoldLandsWithAmount(address recipient, uint256 maxAmount) public onlyOwner {
                  require (publicSaleStartTime > 0 && !claimableActive && !publicSaleActive && !contributorsClaimActive,
                      "Cannot claim the unclaimed if claimable or public sale are active");
                  require(maxAmount <= MAX_MINT_PER_BLOCK, "maxAmount cannot exceed MAX_MINT_PER_BLOCK");
                  require(alphaClaimedAmount < MAX_ALPHA_NFT_AMOUNT || betaClaimedAmount < MAX_BETA_NFT_AMOUNT
                              || mintIndexPublicSaleAndContributors < MAX_LANDS, "Max NFT amount already claimed or sold");
                  uint256 totalMinted;
                  adminClaimStarted = true;
                  //claim beta
                  if(betaClaimedAmount < MAX_BETA_NFT_AMOUNT) {
                      uint256 leftToBeMinted = MAX_BETA_NFT_AMOUNT - betaClaimedAmount;
                      uint256 toMint = leftToBeMinted < maxAmount ? leftToBeMinted : 
                          maxAmount; //take the min
                      uint256 target = betaNftIdCurrent + toMint;
                      for(; betaNftIdCurrent < target; ++betaNftIdCurrent){
                          ++betaClaimedAmount;
                          ++totalMinted;
                          _safeMint(recipient, betaNftIdCurrent);
                      }
                  }
                  //claim alpha
                  if(alphaClaimedAmount < MAX_ALPHA_NFT_AMOUNT) {
                      uint256 leftToBeMinted = MAX_ALPHA_NFT_AMOUNT - alphaClaimedAmount;
                      uint256 toMint = maxAmount < leftToBeMinted + totalMinted ? 
                                      maxAmount :
                                      leftToBeMinted + totalMinted; //summing totalMinted avoid to use another counter
                      
                      uint256 lastAlphaNft = MAX_ALPHA_NFT_AMOUNT - 1;
                      for(uint256 i; i <= lastAlphaNft && totalMinted < toMint; ++i) {
                          if(!alphaClaimed[i]){
                              ++alphaClaimedAmount;
                              ++totalMinted;
                              alphaClaimed[i] = true;
                              _safeMint(recipient, i);
                          }
                      }
                  }
                  //claim unsold
                  if(mintIndexPublicSaleAndContributors < MAX_LANDS){
                      uint256 leftToBeMinted = MAX_LANDS - mintIndexPublicSaleAndContributors; 
                      uint256 toMint = maxAmount < leftToBeMinted + totalMinted ? 
                                      maxAmount :
                                      leftToBeMinted + totalMinted; //summing totalMinted avoid to use another counter
                      for(; mintIndexPublicSaleAndContributors < MAX_LANDS && totalMinted < toMint; ++mintIndexPublicSaleAndContributors) {
                              ++totalMinted;
                              _safeMint(recipient, mintIndexPublicSaleAndContributors);
                      }              
                  }
              }
              //future
              function setFutureMinter(address _futureMinter) external onlyOwner {
                  futureMinter = _futureMinter;
              }
              function mintFutureLands(address recipient) external onlyFutureMinter {
                  mintFutureLandsWithAmount(recipient, MAX_MINT_PER_BLOCK);
              }
              function mintFutureLandsWithAmount(address recipient, uint256 maxAmount) public onlyFutureMinter {
                  require(maxAmount <= MAX_MINT_PER_BLOCK, "maxAmount cannot exceed MAX_MINT_PER_BLOCK");    
                  require(futureLandsNftIdCurrent < MAX_LANDS_WITH_FUTURE, "All future lands were already minted");
                  for(uint256 claimed; claimed < maxAmount && futureLandsNftIdCurrent < MAX_LANDS_WITH_FUTURE; ++claimed){
                      _safeMint(recipient, futureLandsNftIdCurrent++);
                  }
              }
               
              // metadata
              function loadLandMetadata(Metadata memory _landMetadata)
                  external onlyOperator checkMetadataRange(_landMetadata)
                  checkFirstMetadataRange(metadataHashes.length, _landMetadata.startIndex, _landMetadata.endIndex)
              {
                  metadataHashes.push(_landMetadata);
              } 
              function putLandMetadataAtIndex(uint256 index, Metadata memory _landMetadata)
                  external onlyOperator checkMetadataRange(_landMetadata)
                  checkFirstMetadataRange(index, _landMetadata.startIndex, _landMetadata.endIndex)
              {
                  metadataHashes[index] = _landMetadata;
              }     
              // randomness
              function requestRandomnessForPublicSaleAndContributors() external onlyOperator returns (bytes32 requestId) {
                  require(!publicSaleAndContributorsRandomnessRequested, "Public Sale And Contributors Offset already requested");
                  publicSaleAndContributorsRandomnessRequested = true;
                  requestId = requestRandomnessPrivate();
                  isRandomRequestForPublicSaleAndContributors[requestId] = true;
              }
              function requestRandomnessForOwnerClaim() external onlyOperator returns (bytes32 requestId) {
                  require(!ownerClaimRandomnessRequested, "Owner Claim Offset already requested");
                  ownerClaimRandomnessRequested = true;
                  requestId = requestRandomnessPrivate();
                  isRandomRequestForPublicSaleAndContributors[requestId] = false;
              }
              function requestRandomnessPrivate() private returns (bytes32 requestId) {
                  require(
                      LINK.balanceOf(address(this)) >= fee,
                      "Not enough LINK"
                  );
                  return requestRandomness(keyHash, fee);
              }
              function fulfillRandomness(bytes32 requestId, uint256 randomness) internal override {
                  if(isRandomRequestForPublicSaleAndContributors[requestId]){
                      publicSaleAndContributorsOffset = (randomness % (MAX_PUBLIC_SALE_AMOUNT + RESERVED_CONTRIBUTORS_AMOUNT));
                      emit StartingIndexSetPublicSale(publicSaleAndContributorsOffset);
                  } else {
                      alphaOffset = (randomness % MAX_ALPHA_NFT_AMOUNT);
                      betaOffset = (randomness % MAX_BETA_NFT_AMOUNT);
                      emit StartingIndexSetAlphaBeta(alphaOffset, betaOffset);
                  }
              }
          }// SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)
          pragma solidity ^0.8.0;
          /**
           * @dev Interface of the ERC165 standard, as defined in the
           * https://eips.ethereum.org/EIPS/eip-165[EIP].
           *
           * Implementers can declare support of contract interfaces, which can then be
           * queried by others ({ERC165Checker}).
           *
           * For an implementation, see {ERC165}.
           */
          interface IERC165 {
              /**
               * @dev Returns true if this contract implements the interface defined by
               * `interfaceId`. See the corresponding
               * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
               * to learn more about how these ids are created.
               *
               * This function call must use less than 30 000 gas.
               */
              function supportsInterface(bytes4 interfaceId) external view returns (bool);
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)
          pragma solidity ^0.8.0;
          import "./IERC165.sol";
          /**
           * @dev Implementation of the {IERC165} interface.
           *
           * Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check
           * for the additional interface id that will be supported. For example:
           *
           * ```solidity
           * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
           *     return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);
           * }
           * ```
           *
           * Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.
           */
          abstract contract ERC165 is IERC165 {
              /**
               * @dev See {IERC165-supportsInterface}.
               */
              function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
                  return interfaceId == type(IERC165).interfaceId;
              }
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts (last updated v4.5.0) (utils/cryptography/MerkleProof.sol)
          pragma solidity ^0.8.0;
          /**
           * @dev These functions deal with verification of Merkle Trees proofs.
           *
           * The proofs can be generated using the JavaScript library
           * https://github.com/miguelmota/merkletreejs[merkletreejs].
           * Note: the hashing algorithm should be keccak256 and pair sorting should be enabled.
           *
           * See `test/utils/cryptography/MerkleProof.test.js` for some examples.
           */
          library MerkleProof {
              /**
               * @dev Returns true if a `leaf` can be proved to be a part of a Merkle tree
               * defined by `root`. For this, a `proof` must be provided, containing
               * sibling hashes on the branch from the leaf to the root of the tree. Each
               * pair of leaves and each pair of pre-images are assumed to be sorted.
               */
              function verify(
                  bytes32[] memory proof,
                  bytes32 root,
                  bytes32 leaf
              ) internal pure returns (bool) {
                  return processProof(proof, leaf) == root;
              }
              /**
               * @dev Returns the rebuilt hash obtained by traversing a Merklee tree up
               * from `leaf` using `proof`. A `proof` is valid if and only if the rebuilt
               * hash matches the root of the tree. When processing the proof, the pairs
               * of leafs & pre-images are assumed to be sorted.
               *
               * _Available since v4.4._
               */
              function processProof(bytes32[] memory proof, bytes32 leaf) internal pure returns (bytes32) {
                  bytes32 computedHash = leaf;
                  for (uint256 i = 0; i < proof.length; i++) {
                      bytes32 proofElement = proof[i];
                      if (computedHash <= proofElement) {
                          // Hash(current computed hash + current element of the proof)
                          computedHash = _efficientHash(computedHash, proofElement);
                      } else {
                          // Hash(current element of the proof + current computed hash)
                          computedHash = _efficientHash(proofElement, computedHash);
                      }
                  }
                  return computedHash;
              }
              function _efficientHash(bytes32 a, bytes32 b) private pure returns (bytes32 value) {
                  assembly {
                      mstore(0x00, a)
                      mstore(0x20, b)
                      value := keccak256(0x00, 0x40)
                  }
              }
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts v4.4.1 (utils/Strings.sol)
          pragma solidity ^0.8.0;
          /**
           * @dev String operations.
           */
          library Strings {
              bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";
              /**
               * @dev Converts a `uint256` to its ASCII `string` decimal representation.
               */
              function toString(uint256 value) internal pure returns (string memory) {
                  // Inspired by OraclizeAPI's implementation - MIT licence
                  // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol
                  if (value == 0) {
                      return "0";
                  }
                  uint256 temp = value;
                  uint256 digits;
                  while (temp != 0) {
                      digits++;
                      temp /= 10;
                  }
                  bytes memory buffer = new bytes(digits);
                  while (value != 0) {
                      digits -= 1;
                      buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
                      value /= 10;
                  }
                  return string(buffer);
              }
              /**
               * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
               */
              function toHexString(uint256 value) internal pure returns (string memory) {
                  if (value == 0) {
                      return "0x00";
                  }
                  uint256 temp = value;
                  uint256 length = 0;
                  while (temp != 0) {
                      length++;
                      temp >>= 8;
                  }
                  return toHexString(value, length);
              }
              /**
               * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
               */
              function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
                  bytes memory buffer = new bytes(2 * length + 2);
                  buffer[0] = "0";
                  buffer[1] = "x";
                  for (uint256 i = 2 * length + 1; i > 1; --i) {
                      buffer[i] = _HEX_SYMBOLS[value & 0xf];
                      value >>= 4;
                  }
                  require(value == 0, "Strings: hex length insufficient");
                  return string(buffer);
              }
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
          pragma solidity ^0.8.0;
          /**
           * @dev Provides information about the current execution context, including the
           * sender of the transaction and its data. While these are generally available
           * via msg.sender and msg.data, they should not be accessed in such a direct
           * manner, since when dealing with meta-transactions the account sending and
           * paying for execution may not be the actual sender (as far as an application
           * is concerned).
           *
           * This contract is only required for intermediate, library-like contracts.
           */
          abstract contract Context {
              function _msgSender() internal view virtual returns (address) {
                  return msg.sender;
              }
              function _msgData() internal view virtual returns (bytes calldata) {
                  return msg.data;
              }
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts (last updated v4.5.0) (utils/Address.sol)
          pragma solidity ^0.8.1;
          /**
           * @dev Collection of functions related to the address type
           */
          library Address {
              /**
               * @dev Returns true if `account` is a contract.
               *
               * [IMPORTANT]
               * ====
               * It is unsafe to assume that an address for which this function returns
               * false is an externally-owned account (EOA) and not a contract.
               *
               * Among others, `isContract` will return false for the following
               * types of addresses:
               *
               *  - an externally-owned account
               *  - a contract in construction
               *  - an address where a contract will be created
               *  - an address where a contract lived, but was destroyed
               * ====
               *
               * [IMPORTANT]
               * ====
               * You shouldn't rely on `isContract` to protect against flash loan attacks!
               *
               * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
               * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
               * constructor.
               * ====
               */
              function isContract(address account) internal view returns (bool) {
                  // This method relies on extcodesize/address.code.length, which returns 0
                  // for contracts in construction, since the code is only stored at the end
                  // of the constructor execution.
                  return account.code.length > 0;
              }
              /**
               * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
               * `recipient`, forwarding all available gas and reverting on errors.
               *
               * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
               * of certain opcodes, possibly making contracts go over the 2300 gas limit
               * imposed by `transfer`, making them unable to receive funds via
               * `transfer`. {sendValue} removes this limitation.
               *
               * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
               *
               * IMPORTANT: because control is transferred to `recipient`, care must be
               * taken to not create reentrancy vulnerabilities. Consider using
               * {ReentrancyGuard} or the
               * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
               */
              function sendValue(address payable recipient, uint256 amount) internal {
                  require(address(this).balance >= amount, "Address: insufficient balance");
                  (bool success, ) = recipient.call{value: amount}("");
                  require(success, "Address: unable to send value, recipient may have reverted");
              }
              /**
               * @dev Performs a Solidity function call using a low level `call`. A
               * plain `call` is an unsafe replacement for a function call: use this
               * function instead.
               *
               * If `target` reverts with a revert reason, it is bubbled up by this
               * function (like regular Solidity function calls).
               *
               * Returns the raw returned data. To convert to the expected return value,
               * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
               *
               * Requirements:
               *
               * - `target` must be a contract.
               * - calling `target` with `data` must not revert.
               *
               * _Available since v3.1._
               */
              function functionCall(address target, bytes memory data) internal returns (bytes memory) {
                  return functionCall(target, data, "Address: low-level call failed");
              }
              /**
               * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
               * `errorMessage` as a fallback revert reason when `target` reverts.
               *
               * _Available since v3.1._
               */
              function functionCall(
                  address target,
                  bytes memory data,
                  string memory errorMessage
              ) internal returns (bytes memory) {
                  return functionCallWithValue(target, data, 0, errorMessage);
              }
              /**
               * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
               * but also transferring `value` wei to `target`.
               *
               * Requirements:
               *
               * - the calling contract must have an ETH balance of at least `value`.
               * - the called Solidity function must be `payable`.
               *
               * _Available since v3.1._
               */
              function functionCallWithValue(
                  address target,
                  bytes memory data,
                  uint256 value
              ) internal returns (bytes memory) {
                  return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
              }
              /**
               * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
               * with `errorMessage` as a fallback revert reason when `target` reverts.
               *
               * _Available since v3.1._
               */
              function functionCallWithValue(
                  address target,
                  bytes memory data,
                  uint256 value,
                  string memory errorMessage
              ) internal returns (bytes memory) {
                  require(address(this).balance >= value, "Address: insufficient balance for call");
                  require(isContract(target), "Address: call to non-contract");
                  (bool success, bytes memory returndata) = target.call{value: value}(data);
                  return verifyCallResult(success, returndata, errorMessage);
              }
              /**
               * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
               * but performing a static call.
               *
               * _Available since v3.3._
               */
              function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
                  return functionStaticCall(target, data, "Address: low-level static call failed");
              }
              /**
               * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
               * but performing a static call.
               *
               * _Available since v3.3._
               */
              function functionStaticCall(
                  address target,
                  bytes memory data,
                  string memory errorMessage
              ) internal view returns (bytes memory) {
                  require(isContract(target), "Address: static call to non-contract");
                  (bool success, bytes memory returndata) = target.staticcall(data);
                  return verifyCallResult(success, returndata, errorMessage);
              }
              /**
               * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
               * but performing a delegate call.
               *
               * _Available since v3.4._
               */
              function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
                  return functionDelegateCall(target, data, "Address: low-level delegate call failed");
              }
              /**
               * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
               * but performing a delegate call.
               *
               * _Available since v3.4._
               */
              function functionDelegateCall(
                  address target,
                  bytes memory data,
                  string memory errorMessage
              ) internal returns (bytes memory) {
                  require(isContract(target), "Address: delegate call to non-contract");
                  (bool success, bytes memory returndata) = target.delegatecall(data);
                  return verifyCallResult(success, returndata, errorMessage);
              }
              /**
               * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
               * revert reason using the provided one.
               *
               * _Available since v4.3._
               */
              function verifyCallResult(
                  bool success,
                  bytes memory returndata,
                  string memory errorMessage
              ) internal pure returns (bytes memory) {
                  if (success) {
                      return returndata;
                  } else {
                      // Look for revert reason and bubble it up if present
                      if (returndata.length > 0) {
                          // The easiest way to bubble the revert reason is using memory via assembly
                          assembly {
                              let returndata_size := mload(returndata)
                              revert(add(32, returndata), returndata_size)
                          }
                      } else {
                          revert(errorMessage);
                      }
                  }
              }
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/IERC721Metadata.sol)
          pragma solidity ^0.8.0;
          import "../IERC721.sol";
          /**
           * @title ERC-721 Non-Fungible Token Standard, optional metadata extension
           * @dev See https://eips.ethereum.org/EIPS/eip-721
           */
          interface IERC721Metadata is IERC721 {
              /**
               * @dev Returns the token collection name.
               */
              function name() external view returns (string memory);
              /**
               * @dev Returns the token collection symbol.
               */
              function symbol() external view returns (string memory);
              /**
               * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.
               */
              function tokenURI(uint256 tokenId) external view returns (string memory);
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts (last updated v4.5.0) (token/ERC721/extensions/IERC721Enumerable.sol)
          pragma solidity ^0.8.0;
          import "../IERC721.sol";
          /**
           * @title ERC-721 Non-Fungible Token Standard, optional enumeration extension
           * @dev See https://eips.ethereum.org/EIPS/eip-721
           */
          interface IERC721Enumerable is IERC721 {
              /**
               * @dev Returns the total amount of tokens stored by the contract.
               */
              function totalSupply() external view returns (uint256);
              /**
               * @dev Returns a token ID owned by `owner` at a given `index` of its token list.
               * Use along with {balanceOf} to enumerate all of ``owner``'s tokens.
               */
              function tokenOfOwnerByIndex(address owner, uint256 index) external view returns (uint256);
              /**
               * @dev Returns a token ID at a given `index` of all the tokens stored by the contract.
               * Use along with {totalSupply} to enumerate all tokens.
               */
              function tokenByIndex(uint256 index) external view returns (uint256);
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/ERC721Enumerable.sol)
          pragma solidity ^0.8.0;
          import "../ERC721.sol";
          import "./IERC721Enumerable.sol";
          /**
           * @dev This implements an optional extension of {ERC721} defined in the EIP that adds
           * enumerability of all the token ids in the contract as well as all token ids owned by each
           * account.
           */
          abstract contract ERC721Enumerable is ERC721, IERC721Enumerable {
              // Mapping from owner to list of owned token IDs
              mapping(address => mapping(uint256 => uint256)) private _ownedTokens;
              // Mapping from token ID to index of the owner tokens list
              mapping(uint256 => uint256) private _ownedTokensIndex;
              // Array with all token ids, used for enumeration
              uint256[] private _allTokens;
              // Mapping from token id to position in the allTokens array
              mapping(uint256 => uint256) private _allTokensIndex;
              /**
               * @dev See {IERC165-supportsInterface}.
               */
              function supportsInterface(bytes4 interfaceId) public view virtual override(IERC165, ERC721) returns (bool) {
                  return interfaceId == type(IERC721Enumerable).interfaceId || super.supportsInterface(interfaceId);
              }
              /**
               * @dev See {IERC721Enumerable-tokenOfOwnerByIndex}.
               */
              function tokenOfOwnerByIndex(address owner, uint256 index) public view virtual override returns (uint256) {
                  require(index < ERC721.balanceOf(owner), "ERC721Enumerable: owner index out of bounds");
                  return _ownedTokens[owner][index];
              }
              /**
               * @dev See {IERC721Enumerable-totalSupply}.
               */
              function totalSupply() public view virtual override returns (uint256) {
                  return _allTokens.length;
              }
              /**
               * @dev See {IERC721Enumerable-tokenByIndex}.
               */
              function tokenByIndex(uint256 index) public view virtual override returns (uint256) {
                  require(index < ERC721Enumerable.totalSupply(), "ERC721Enumerable: global index out of bounds");
                  return _allTokens[index];
              }
              /**
               * @dev Hook that is called before any token transfer. This includes minting
               * and burning.
               *
               * Calling conditions:
               *
               * - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
               * transferred to `to`.
               * - When `from` is zero, `tokenId` will be minted for `to`.
               * - When `to` is zero, ``from``'s `tokenId` will be burned.
               * - `from` cannot be the zero address.
               * - `to` cannot be the zero address.
               *
               * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
               */
              function _beforeTokenTransfer(
                  address from,
                  address to,
                  uint256 tokenId
              ) internal virtual override {
                  super._beforeTokenTransfer(from, to, tokenId);
                  if (from == address(0)) {
                      _addTokenToAllTokensEnumeration(tokenId);
                  } else if (from != to) {
                      _removeTokenFromOwnerEnumeration(from, tokenId);
                  }
                  if (to == address(0)) {
                      _removeTokenFromAllTokensEnumeration(tokenId);
                  } else if (to != from) {
                      _addTokenToOwnerEnumeration(to, tokenId);
                  }
              }
              /**
               * @dev Private function to add a token to this extension's ownership-tracking data structures.
               * @param to address representing the new owner of the given token ID
               * @param tokenId uint256 ID of the token to be added to the tokens list of the given address
               */
              function _addTokenToOwnerEnumeration(address to, uint256 tokenId) private {
                  uint256 length = ERC721.balanceOf(to);
                  _ownedTokens[to][length] = tokenId;
                  _ownedTokensIndex[tokenId] = length;
              }
              /**
               * @dev Private function to add a token to this extension's token tracking data structures.
               * @param tokenId uint256 ID of the token to be added to the tokens list
               */
              function _addTokenToAllTokensEnumeration(uint256 tokenId) private {
                  _allTokensIndex[tokenId] = _allTokens.length;
                  _allTokens.push(tokenId);
              }
              /**
               * @dev Private function to remove a token from this extension's ownership-tracking data structures. Note that
               * while the token is not assigned a new owner, the `_ownedTokensIndex` mapping is _not_ updated: this allows for
               * gas optimizations e.g. when performing a transfer operation (avoiding double writes).
               * This has O(1) time complexity, but alters the order of the _ownedTokens array.
               * @param from address representing the previous owner of the given token ID
               * @param tokenId uint256 ID of the token to be removed from the tokens list of the given address
               */
              function _removeTokenFromOwnerEnumeration(address from, uint256 tokenId) private {
                  // To prevent a gap in from's tokens array, we store the last token in the index of the token to delete, and
                  // then delete the last slot (swap and pop).
                  uint256 lastTokenIndex = ERC721.balanceOf(from) - 1;
                  uint256 tokenIndex = _ownedTokensIndex[tokenId];
                  // When the token to delete is the last token, the swap operation is unnecessary
                  if (tokenIndex != lastTokenIndex) {
                      uint256 lastTokenId = _ownedTokens[from][lastTokenIndex];
                      _ownedTokens[from][tokenIndex] = lastTokenId; // Move the last token to the slot of the to-delete token
                      _ownedTokensIndex[lastTokenId] = tokenIndex; // Update the moved token's index
                  }
                  // This also deletes the contents at the last position of the array
                  delete _ownedTokensIndex[tokenId];
                  delete _ownedTokens[from][lastTokenIndex];
              }
              /**
               * @dev Private function to remove a token from this extension's token tracking data structures.
               * This has O(1) time complexity, but alters the order of the _allTokens array.
               * @param tokenId uint256 ID of the token to be removed from the tokens list
               */
              function _removeTokenFromAllTokensEnumeration(uint256 tokenId) private {
                  // To prevent a gap in the tokens array, we store the last token in the index of the token to delete, and
                  // then delete the last slot (swap and pop).
                  uint256 lastTokenIndex = _allTokens.length - 1;
                  uint256 tokenIndex = _allTokensIndex[tokenId];
                  // When the token to delete is the last token, the swap operation is unnecessary. However, since this occurs so
                  // rarely (when the last minted token is burnt) that we still do the swap here to avoid the gas cost of adding
                  // an 'if' statement (like in _removeTokenFromOwnerEnumeration)
                  uint256 lastTokenId = _allTokens[lastTokenIndex];
                  _allTokens[tokenIndex] = lastTokenId; // Move the last token to the slot of the to-delete token
                  _allTokensIndex[lastTokenId] = tokenIndex; // Update the moved token's index
                  // This also deletes the contents at the last position of the array
                  delete _allTokensIndex[tokenId];
                  _allTokens.pop();
              }
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721Receiver.sol)
          pragma solidity ^0.8.0;
          /**
           * @title ERC721 token receiver interface
           * @dev Interface for any contract that wants to support safeTransfers
           * from ERC721 asset contracts.
           */
          interface IERC721Receiver {
              /**
               * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
               * by `operator` from `from`, this function is called.
               *
               * It must return its Solidity selector to confirm the token transfer.
               * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
               *
               * The selector can be obtained in Solidity with `IERC721.onERC721Received.selector`.
               */
              function onERC721Received(
                  address operator,
                  address from,
                  uint256 tokenId,
                  bytes calldata data
              ) external returns (bytes4);
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721.sol)
          pragma solidity ^0.8.0;
          import "../../utils/introspection/IERC165.sol";
          /**
           * @dev Required interface of an ERC721 compliant contract.
           */
          interface IERC721 is IERC165 {
              /**
               * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
               */
              event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);
              /**
               * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
               */
              event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);
              /**
               * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
               */
              event ApprovalForAll(address indexed owner, address indexed operator, bool approved);
              /**
               * @dev Returns the number of tokens in ``owner``'s account.
               */
              function balanceOf(address owner) external view returns (uint256 balance);
              /**
               * @dev Returns the owner of the `tokenId` token.
               *
               * Requirements:
               *
               * - `tokenId` must exist.
               */
              function ownerOf(uint256 tokenId) external view returns (address owner);
              /**
               * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
               * are aware of the ERC721 protocol to prevent tokens from being forever locked.
               *
               * Requirements:
               *
               * - `from` cannot be the zero address.
               * - `to` cannot be the zero address.
               * - `tokenId` token must exist and be owned by `from`.
               * - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}.
               * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
               *
               * Emits a {Transfer} event.
               */
              function safeTransferFrom(
                  address from,
                  address to,
                  uint256 tokenId
              ) external;
              /**
               * @dev Transfers `tokenId` token from `from` to `to`.
               *
               * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
               *
               * Requirements:
               *
               * - `from` cannot be the zero address.
               * - `to` cannot be the zero address.
               * - `tokenId` token must be owned by `from`.
               * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
               *
               * Emits a {Transfer} event.
               */
              function transferFrom(
                  address from,
                  address to,
                  uint256 tokenId
              ) external;
              /**
               * @dev Gives permission to `to` to transfer `tokenId` token to another account.
               * The approval is cleared when the token is transferred.
               *
               * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
               *
               * Requirements:
               *
               * - The caller must own the token or be an approved operator.
               * - `tokenId` must exist.
               *
               * Emits an {Approval} event.
               */
              function approve(address to, uint256 tokenId) external;
              /**
               * @dev Returns the account approved for `tokenId` token.
               *
               * Requirements:
               *
               * - `tokenId` must exist.
               */
              function getApproved(uint256 tokenId) external view returns (address operator);
              /**
               * @dev Approve or remove `operator` as an operator for the caller.
               * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
               *
               * Requirements:
               *
               * - The `operator` cannot be the caller.
               *
               * Emits an {ApprovalForAll} event.
               */
              function setApprovalForAll(address operator, bool _approved) external;
              /**
               * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
               *
               * See {setApprovalForAll}
               */
              function isApprovedForAll(address owner, address operator) external view returns (bool);
              /**
               * @dev Safely transfers `tokenId` token from `from` to `to`.
               *
               * Requirements:
               *
               * - `from` cannot be the zero address.
               * - `to` cannot be the zero address.
               * - `tokenId` token must exist and be owned by `from`.
               * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
               * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
               *
               * Emits a {Transfer} event.
               */
              function safeTransferFrom(
                  address from,
                  address to,
                  uint256 tokenId,
                  bytes calldata data
              ) external;
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts (last updated v4.5.0) (token/ERC721/ERC721.sol)
          pragma solidity ^0.8.0;
          import "./IERC721.sol";
          import "./IERC721Receiver.sol";
          import "./extensions/IERC721Metadata.sol";
          import "../../utils/Address.sol";
          import "../../utils/Context.sol";
          import "../../utils/Strings.sol";
          import "../../utils/introspection/ERC165.sol";
          /**
           * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
           * the Metadata extension, but not including the Enumerable extension, which is available separately as
           * {ERC721Enumerable}.
           */
          contract ERC721 is Context, ERC165, IERC721, IERC721Metadata {
              using Address for address;
              using Strings for uint256;
              // Token name
              string private _name;
              // Token symbol
              string private _symbol;
              // Mapping from token ID to owner address
              mapping(uint256 => address) private _owners;
              // Mapping owner address to token count
              mapping(address => uint256) private _balances;
              // Mapping from token ID to approved address
              mapping(uint256 => address) private _tokenApprovals;
              // Mapping from owner to operator approvals
              mapping(address => mapping(address => bool)) private _operatorApprovals;
              /**
               * @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.
               */
              constructor(string memory name_, string memory symbol_) {
                  _name = name_;
                  _symbol = symbol_;
              }
              /**
               * @dev See {IERC165-supportsInterface}.
               */
              function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
                  return
                      interfaceId == type(IERC721).interfaceId ||
                      interfaceId == type(IERC721Metadata).interfaceId ||
                      super.supportsInterface(interfaceId);
              }
              /**
               * @dev See {IERC721-balanceOf}.
               */
              function balanceOf(address owner) public view virtual override returns (uint256) {
                  require(owner != address(0), "ERC721: balance query for the zero address");
                  return _balances[owner];
              }
              /**
               * @dev See {IERC721-ownerOf}.
               */
              function ownerOf(uint256 tokenId) public view virtual override returns (address) {
                  address owner = _owners[tokenId];
                  require(owner != address(0), "ERC721: owner query for nonexistent token");
                  return owner;
              }
              /**
               * @dev See {IERC721Metadata-name}.
               */
              function name() public view virtual override returns (string memory) {
                  return _name;
              }
              /**
               * @dev See {IERC721Metadata-symbol}.
               */
              function symbol() public view virtual override returns (string memory) {
                  return _symbol;
              }
              /**
               * @dev See {IERC721Metadata-tokenURI}.
               */
              function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
                  require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");
                  string memory baseURI = _baseURI();
                  return bytes(baseURI).length > 0 ? string(abi.encodePacked(baseURI, tokenId.toString())) : "";
              }
              /**
               * @dev Base URI for computing {tokenURI}. If set, the resulting URI for each
               * token will be the concatenation of the `baseURI` and the `tokenId`. Empty
               * by default, can be overriden in child contracts.
               */
              function _baseURI() internal view virtual returns (string memory) {
                  return "";
              }
              /**
               * @dev See {IERC721-approve}.
               */
              function approve(address to, uint256 tokenId) public virtual override {
                  address owner = ERC721.ownerOf(tokenId);
                  require(to != owner, "ERC721: approval to current owner");
                  require(
                      _msgSender() == owner || isApprovedForAll(owner, _msgSender()),
                      "ERC721: approve caller is not owner nor approved for all"
                  );
                  _approve(to, tokenId);
              }
              /**
               * @dev See {IERC721-getApproved}.
               */
              function getApproved(uint256 tokenId) public view virtual override returns (address) {
                  require(_exists(tokenId), "ERC721: approved query for nonexistent token");
                  return _tokenApprovals[tokenId];
              }
              /**
               * @dev See {IERC721-setApprovalForAll}.
               */
              function setApprovalForAll(address operator, bool approved) public virtual override {
                  _setApprovalForAll(_msgSender(), operator, approved);
              }
              /**
               * @dev See {IERC721-isApprovedForAll}.
               */
              function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {
                  return _operatorApprovals[owner][operator];
              }
              /**
               * @dev See {IERC721-transferFrom}.
               */
              function transferFrom(
                  address from,
                  address to,
                  uint256 tokenId
              ) public virtual override {
                  //solhint-disable-next-line max-line-length
                  require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
                  _transfer(from, to, tokenId);
              }
              /**
               * @dev See {IERC721-safeTransferFrom}.
               */
              function safeTransferFrom(
                  address from,
                  address to,
                  uint256 tokenId
              ) public virtual override {
                  safeTransferFrom(from, to, tokenId, "");
              }
              /**
               * @dev See {IERC721-safeTransferFrom}.
               */
              function safeTransferFrom(
                  address from,
                  address to,
                  uint256 tokenId,
                  bytes memory _data
              ) public virtual override {
                  require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
                  _safeTransfer(from, to, tokenId, _data);
              }
              /**
               * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
               * are aware of the ERC721 protocol to prevent tokens from being forever locked.
               *
               * `_data` is additional data, it has no specified format and it is sent in call to `to`.
               *
               * This internal function is equivalent to {safeTransferFrom}, and can be used to e.g.
               * implement alternative mechanisms to perform token transfer, such as signature-based.
               *
               * Requirements:
               *
               * - `from` cannot be the zero address.
               * - `to` cannot be the zero address.
               * - `tokenId` token must exist and be owned by `from`.
               * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
               *
               * Emits a {Transfer} event.
               */
              function _safeTransfer(
                  address from,
                  address to,
                  uint256 tokenId,
                  bytes memory _data
              ) internal virtual {
                  _transfer(from, to, tokenId);
                  require(_checkOnERC721Received(from, to, tokenId, _data), "ERC721: transfer to non ERC721Receiver implementer");
              }
              /**
               * @dev Returns whether `tokenId` exists.
               *
               * Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.
               *
               * Tokens start existing when they are minted (`_mint`),
               * and stop existing when they are burned (`_burn`).
               */
              function _exists(uint256 tokenId) internal view virtual returns (bool) {
                  return _owners[tokenId] != address(0);
              }
              /**
               * @dev Returns whether `spender` is allowed to manage `tokenId`.
               *
               * Requirements:
               *
               * - `tokenId` must exist.
               */
              function _isApprovedOrOwner(address spender, uint256 tokenId) internal view virtual returns (bool) {
                  require(_exists(tokenId), "ERC721: operator query for nonexistent token");
                  address owner = ERC721.ownerOf(tokenId);
                  return (spender == owner || getApproved(tokenId) == spender || isApprovedForAll(owner, spender));
              }
              /**
               * @dev Safely mints `tokenId` and transfers it to `to`.
               *
               * Requirements:
               *
               * - `tokenId` must not exist.
               * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
               *
               * Emits a {Transfer} event.
               */
              function _safeMint(address to, uint256 tokenId) internal virtual {
                  _safeMint(to, tokenId, "");
              }
              /**
               * @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is
               * forwarded in {IERC721Receiver-onERC721Received} to contract recipients.
               */
              function _safeMint(
                  address to,
                  uint256 tokenId,
                  bytes memory _data
              ) internal virtual {
                  _mint(to, tokenId);
                  require(
                      _checkOnERC721Received(address(0), to, tokenId, _data),
                      "ERC721: transfer to non ERC721Receiver implementer"
                  );
              }
              /**
               * @dev Mints `tokenId` and transfers it to `to`.
               *
               * WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible
               *
               * Requirements:
               *
               * - `tokenId` must not exist.
               * - `to` cannot be the zero address.
               *
               * Emits a {Transfer} event.
               */
              function _mint(address to, uint256 tokenId) internal virtual {
                  require(to != address(0), "ERC721: mint to the zero address");
                  require(!_exists(tokenId), "ERC721: token already minted");
                  _beforeTokenTransfer(address(0), to, tokenId);
                  _balances[to] += 1;
                  _owners[tokenId] = to;
                  emit Transfer(address(0), to, tokenId);
                  _afterTokenTransfer(address(0), to, tokenId);
              }
              /**
               * @dev Destroys `tokenId`.
               * The approval is cleared when the token is burned.
               *
               * Requirements:
               *
               * - `tokenId` must exist.
               *
               * Emits a {Transfer} event.
               */
              function _burn(uint256 tokenId) internal virtual {
                  address owner = ERC721.ownerOf(tokenId);
                  _beforeTokenTransfer(owner, address(0), tokenId);
                  // Clear approvals
                  _approve(address(0), tokenId);
                  _balances[owner] -= 1;
                  delete _owners[tokenId];
                  emit Transfer(owner, address(0), tokenId);
                  _afterTokenTransfer(owner, address(0), tokenId);
              }
              /**
               * @dev Transfers `tokenId` from `from` to `to`.
               *  As opposed to {transferFrom}, this imposes no restrictions on msg.sender.
               *
               * Requirements:
               *
               * - `to` cannot be the zero address.
               * - `tokenId` token must be owned by `from`.
               *
               * Emits a {Transfer} event.
               */
              function _transfer(
                  address from,
                  address to,
                  uint256 tokenId
              ) internal virtual {
                  require(ERC721.ownerOf(tokenId) == from, "ERC721: transfer from incorrect owner");
                  require(to != address(0), "ERC721: transfer to the zero address");
                  _beforeTokenTransfer(from, to, tokenId);
                  // Clear approvals from the previous owner
                  _approve(address(0), tokenId);
                  _balances[from] -= 1;
                  _balances[to] += 1;
                  _owners[tokenId] = to;
                  emit Transfer(from, to, tokenId);
                  _afterTokenTransfer(from, to, tokenId);
              }
              /**
               * @dev Approve `to` to operate on `tokenId`
               *
               * Emits a {Approval} event.
               */
              function _approve(address to, uint256 tokenId) internal virtual {
                  _tokenApprovals[tokenId] = to;
                  emit Approval(ERC721.ownerOf(tokenId), to, tokenId);
              }
              /**
               * @dev Approve `operator` to operate on all of `owner` tokens
               *
               * Emits a {ApprovalForAll} event.
               */
              function _setApprovalForAll(
                  address owner,
                  address operator,
                  bool approved
              ) internal virtual {
                  require(owner != operator, "ERC721: approve to caller");
                  _operatorApprovals[owner][operator] = approved;
                  emit ApprovalForAll(owner, operator, approved);
              }
              /**
               * @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address.
               * The call is not executed if the target address is not a contract.
               *
               * @param from address representing the previous owner of the given token ID
               * @param to target address that will receive the tokens
               * @param tokenId uint256 ID of the token to be transferred
               * @param _data bytes optional data to send along with the call
               * @return bool whether the call correctly returned the expected magic value
               */
              function _checkOnERC721Received(
                  address from,
                  address to,
                  uint256 tokenId,
                  bytes memory _data
              ) private returns (bool) {
                  if (to.isContract()) {
                      try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, _data) returns (bytes4 retval) {
                          return retval == IERC721Receiver.onERC721Received.selector;
                      } catch (bytes memory reason) {
                          if (reason.length == 0) {
                              revert("ERC721: transfer to non ERC721Receiver implementer");
                          } else {
                              assembly {
                                  revert(add(32, reason), mload(reason))
                              }
                          }
                      }
                  } else {
                      return true;
                  }
              }
              /**
               * @dev Hook that is called before any token transfer. This includes minting
               * and burning.
               *
               * Calling conditions:
               *
               * - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
               * transferred to `to`.
               * - When `from` is zero, `tokenId` will be minted for `to`.
               * - When `to` is zero, ``from``'s `tokenId` will be burned.
               * - `from` and `to` are never both zero.
               *
               * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
               */
              function _beforeTokenTransfer(
                  address from,
                  address to,
                  uint256 tokenId
              ) internal virtual {}
              /**
               * @dev Hook that is called after any transfer of tokens. This includes
               * minting and burning.
               *
               * Calling conditions:
               *
               * - when `from` and `to` are both non-zero.
               * - `from` and `to` are never both zero.
               *
               * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
               */
              function _afterTokenTransfer(
                  address from,
                  address to,
                  uint256 tokenId
              ) internal virtual {}
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts v4.4.1 (token/ERC20/utils/SafeERC20.sol)
          pragma solidity ^0.8.0;
          import "../IERC20.sol";
          import "../../../utils/Address.sol";
          /**
           * @title SafeERC20
           * @dev Wrappers around ERC20 operations that throw on failure (when the token
           * contract returns false). Tokens that return no value (and instead revert or
           * throw on failure) are also supported, non-reverting calls are assumed to be
           * successful.
           * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
           * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
           */
          library SafeERC20 {
              using Address for address;
              function safeTransfer(
                  IERC20 token,
                  address to,
                  uint256 value
              ) internal {
                  _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
              }
              function safeTransferFrom(
                  IERC20 token,
                  address from,
                  address to,
                  uint256 value
              ) internal {
                  _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
              }
              /**
               * @dev Deprecated. This function has issues similar to the ones found in
               * {IERC20-approve}, and its usage is discouraged.
               *
               * Whenever possible, use {safeIncreaseAllowance} and
               * {safeDecreaseAllowance} instead.
               */
              function safeApprove(
                  IERC20 token,
                  address spender,
                  uint256 value
              ) internal {
                  // safeApprove should only be called when setting an initial allowance,
                  // or when resetting it to zero. To increase and decrease it, use
                  // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
                  require(
                      (value == 0) || (token.allowance(address(this), spender) == 0),
                      "SafeERC20: approve from non-zero to non-zero allowance"
                  );
                  _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
              }
              function safeIncreaseAllowance(
                  IERC20 token,
                  address spender,
                  uint256 value
              ) internal {
                  uint256 newAllowance = token.allowance(address(this), spender) + value;
                  _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
              }
              function safeDecreaseAllowance(
                  IERC20 token,
                  address spender,
                  uint256 value
              ) internal {
                  unchecked {
                      uint256 oldAllowance = token.allowance(address(this), spender);
                      require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
                      uint256 newAllowance = oldAllowance - value;
                      _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
                  }
              }
              /**
               * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
               * on the return value: the return value is optional (but if data is returned, it must not be false).
               * @param token The token targeted by the call.
               * @param data The call data (encoded using abi.encode or one of its variants).
               */
              function _callOptionalReturn(IERC20 token, bytes memory data) private {
                  // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
                  // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
                  // the target address contains contract code and also asserts for success in the low-level call.
                  bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
                  if (returndata.length > 0) {
                      // Return data is optional
                      require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
                  }
              }
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts (last updated v4.5.0) (token/ERC20/IERC20.sol)
          pragma solidity ^0.8.0;
          /**
           * @dev Interface of the ERC20 standard as defined in the EIP.
           */
          interface IERC20 {
              /**
               * @dev Returns the amount of tokens in existence.
               */
              function totalSupply() external view returns (uint256);
              /**
               * @dev Returns the amount of tokens owned by `account`.
               */
              function balanceOf(address account) external view returns (uint256);
              /**
               * @dev Moves `amount` tokens from the caller's account to `to`.
               *
               * Returns a boolean value indicating whether the operation succeeded.
               *
               * Emits a {Transfer} event.
               */
              function transfer(address to, uint256 amount) external returns (bool);
              /**
               * @dev Returns the remaining number of tokens that `spender` will be
               * allowed to spend on behalf of `owner` through {transferFrom}. This is
               * zero by default.
               *
               * This value changes when {approve} or {transferFrom} are called.
               */
              function allowance(address owner, address spender) external view returns (uint256);
              /**
               * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
               *
               * Returns a boolean value indicating whether the operation succeeded.
               *
               * IMPORTANT: Beware that changing an allowance with this method brings the risk
               * that someone may use both the old and the new allowance by unfortunate
               * transaction ordering. One possible solution to mitigate this race
               * condition is to first reduce the spender's allowance to 0 and set the
               * desired value afterwards:
               * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
               *
               * Emits an {Approval} event.
               */
              function approve(address spender, uint256 amount) external returns (bool);
              /**
               * @dev Moves `amount` tokens from `from` to `to` using the
               * allowance mechanism. `amount` is then deducted from the caller's
               * allowance.
               *
               * Returns a boolean value indicating whether the operation succeeded.
               *
               * Emits a {Transfer} event.
               */
              function transferFrom(
                  address from,
                  address to,
                  uint256 amount
              ) external returns (bool);
              /**
               * @dev Emitted when `value` tokens are moved from one account (`from`) to
               * another (`to`).
               *
               * Note that `value` may be zero.
               */
              event Transfer(address indexed from, address indexed to, uint256 value);
              /**
               * @dev Emitted when the allowance of a `spender` for an `owner` is set by
               * a call to {approve}. `value` is the new allowance.
               */
              event Approval(address indexed owner, address indexed spender, uint256 value);
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts v4.4.1 (security/ReentrancyGuard.sol)
          pragma solidity ^0.8.0;
          /**
           * @dev Contract module that helps prevent reentrant calls to a function.
           *
           * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
           * available, which can be applied to functions to make sure there are no nested
           * (reentrant) calls to them.
           *
           * Note that because there is a single `nonReentrant` guard, functions marked as
           * `nonReentrant` may not call one another. This can be worked around by making
           * those functions `private`, and then adding `external` `nonReentrant` entry
           * points to them.
           *
           * TIP: If you would like to learn more about reentrancy and alternative ways
           * to protect against it, check out our blog post
           * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
           */
          abstract contract ReentrancyGuard {
              // Booleans are more expensive than uint256 or any type that takes up a full
              // word because each write operation emits an extra SLOAD to first read the
              // slot's contents, replace the bits taken up by the boolean, and then write
              // back. This is the compiler's defense against contract upgrades and
              // pointer aliasing, and it cannot be disabled.
              // The values being non-zero value makes deployment a bit more expensive,
              // but in exchange the refund on every call to nonReentrant will be lower in
              // amount. Since refunds are capped to a percentage of the total
              // transaction's gas, it is best to keep them low in cases like this one, to
              // increase the likelihood of the full refund coming into effect.
              uint256 private constant _NOT_ENTERED = 1;
              uint256 private constant _ENTERED = 2;
              uint256 private _status;
              constructor() {
                  _status = _NOT_ENTERED;
              }
              /**
               * @dev Prevents a contract from calling itself, directly or indirectly.
               * Calling a `nonReentrant` function from another `nonReentrant`
               * function is not supported. It is possible to prevent this from happening
               * by making the `nonReentrant` function external, and making it call a
               * `private` function that does the actual work.
               */
              modifier nonReentrant() {
                  // On the first call to nonReentrant, _notEntered will be true
                  require(_status != _ENTERED, "ReentrancyGuard: reentrant call");
                  // Any calls to nonReentrant after this point will fail
                  _status = _ENTERED;
                  _;
                  // By storing the original value once again, a refund is triggered (see
                  // https://eips.ethereum.org/EIPS/eip-2200)
                  _status = _NOT_ENTERED;
              }
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)
          pragma solidity ^0.8.0;
          import "../utils/Context.sol";
          /**
           * @dev Contract module which provides a basic access control mechanism, where
           * there is an account (an owner) that can be granted exclusive access to
           * specific functions.
           *
           * By default, the owner account will be the one that deploys the contract. This
           * can later be changed with {transferOwnership}.
           *
           * This module is used through inheritance. It will make available the modifier
           * `onlyOwner`, which can be applied to your functions to restrict their use to
           * the owner.
           */
          abstract contract Ownable is Context {
              address private _owner;
              event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
              /**
               * @dev Initializes the contract setting the deployer as the initial owner.
               */
              constructor() {
                  _transferOwnership(_msgSender());
              }
              /**
               * @dev Returns the address of the current owner.
               */
              function owner() public view virtual returns (address) {
                  return _owner;
              }
              /**
               * @dev Throws if called by any account other than the owner.
               */
              modifier onlyOwner() {
                  require(owner() == _msgSender(), "Ownable: caller is not the owner");
                  _;
              }
              /**
               * @dev Leaves the contract without owner. It will not be possible to call
               * `onlyOwner` functions anymore. Can only be called by the current owner.
               *
               * NOTE: Renouncing ownership will leave the contract without an owner,
               * thereby removing any functionality that is only available to the owner.
               */
              function renounceOwnership() public virtual onlyOwner {
                  _transferOwnership(address(0));
              }
              /**
               * @dev Transfers ownership of the contract to a new account (`newOwner`).
               * Can only be called by the current owner.
               */
              function transferOwnership(address newOwner) public virtual onlyOwner {
                  require(newOwner != address(0), "Ownable: new owner is the zero address");
                  _transferOwnership(newOwner);
              }
              /**
               * @dev Transfers ownership of the contract to a new account (`newOwner`).
               * Internal function without access restriction.
               */
              function _transferOwnership(address newOwner) internal virtual {
                  address oldOwner = _owner;
                  _owner = newOwner;
                  emit OwnershipTransferred(oldOwner, newOwner);
              }
          }
          // SPDX-License-Identifier: MIT
          pragma solidity ^0.8.0;
          interface LinkTokenInterface {
            function allowance(address owner, address spender) external view returns (uint256 remaining);
            function approve(address spender, uint256 value) external returns (bool success);
            function balanceOf(address owner) external view returns (uint256 balance);
            function decimals() external view returns (uint8 decimalPlaces);
            function decreaseApproval(address spender, uint256 addedValue) external returns (bool success);
            function increaseApproval(address spender, uint256 subtractedValue) external;
            function name() external view returns (string memory tokenName);
            function symbol() external view returns (string memory tokenSymbol);
            function totalSupply() external view returns (uint256 totalTokensIssued);
            function transfer(address to, uint256 value) external returns (bool success);
            function transferAndCall(
              address to,
              uint256 value,
              bytes calldata data
            ) external returns (bool success);
            function transferFrom(
              address from,
              address to,
              uint256 value
            ) external returns (bool success);
          }
          // SPDX-License-Identifier: MIT
          pragma solidity ^0.8.0;
          contract VRFRequestIDBase {
            /**
             * @notice returns the seed which is actually input to the VRF coordinator
             *
             * @dev To prevent repetition of VRF output due to repetition of the
             * @dev user-supplied seed, that seed is combined in a hash with the
             * @dev user-specific nonce, and the address of the consuming contract. The
             * @dev risk of repetition is mostly mitigated by inclusion of a blockhash in
             * @dev the final seed, but the nonce does protect against repetition in
             * @dev requests which are included in a single block.
             *
             * @param _userSeed VRF seed input provided by user
             * @param _requester Address of the requesting contract
             * @param _nonce User-specific nonce at the time of the request
             */
            function makeVRFInputSeed(
              bytes32 _keyHash,
              uint256 _userSeed,
              address _requester,
              uint256 _nonce
            ) internal pure returns (uint256) {
              return uint256(keccak256(abi.encode(_keyHash, _userSeed, _requester, _nonce)));
            }
            /**
             * @notice Returns the id for this request
             * @param _keyHash The serviceAgreement ID to be used for this request
             * @param _vRFInputSeed The seed to be passed directly to the VRF
             * @return The id for this request
             *
             * @dev Note that _vRFInputSeed is not the seed passed by the consuming
             * @dev contract, but the one generated by makeVRFInputSeed
             */
            function makeRequestId(bytes32 _keyHash, uint256 _vRFInputSeed) internal pure returns (bytes32) {
              return keccak256(abi.encodePacked(_keyHash, _vRFInputSeed));
            }
          }
          // SPDX-License-Identifier: MIT
          pragma solidity ^0.8.0;
          import "./interfaces/LinkTokenInterface.sol";
          import "./VRFRequestIDBase.sol";
          /** ****************************************************************************
           * @notice Interface for contracts using VRF randomness
           * *****************************************************************************
           * @dev PURPOSE
           *
           * @dev Reggie the Random Oracle (not his real job) wants to provide randomness
           * @dev to Vera the verifier in such a way that Vera can be sure he's not
           * @dev making his output up to suit himself. Reggie provides Vera a public key
           * @dev to which he knows the secret key. Each time Vera provides a seed to
           * @dev Reggie, he gives back a value which is computed completely
           * @dev deterministically from the seed and the secret key.
           *
           * @dev Reggie provides a proof by which Vera can verify that the output was
           * @dev correctly computed once Reggie tells it to her, but without that proof,
           * @dev the output is indistinguishable to her from a uniform random sample
           * @dev from the output space.
           *
           * @dev The purpose of this contract is to make it easy for unrelated contracts
           * @dev to talk to Vera the verifier about the work Reggie is doing, to provide
           * @dev simple access to a verifiable source of randomness.
           * *****************************************************************************
           * @dev USAGE
           *
           * @dev Calling contracts must inherit from VRFConsumerBase, and can
           * @dev initialize VRFConsumerBase's attributes in their constructor as
           * @dev shown:
           *
           * @dev   contract VRFConsumer {
           * @dev     constuctor(<other arguments>, address _vrfCoordinator, address _link)
           * @dev       VRFConsumerBase(_vrfCoordinator, _link) public {
           * @dev         <initialization with other arguments goes here>
           * @dev       }
           * @dev   }
           *
           * @dev The oracle will have given you an ID for the VRF keypair they have
           * @dev committed to (let's call it keyHash), and have told you the minimum LINK
           * @dev price for VRF service. Make sure your contract has sufficient LINK, and
           * @dev call requestRandomness(keyHash, fee, seed), where seed is the input you
           * @dev want to generate randomness from.
           *
           * @dev Once the VRFCoordinator has received and validated the oracle's response
           * @dev to your request, it will call your contract's fulfillRandomness method.
           *
           * @dev The randomness argument to fulfillRandomness is the actual random value
           * @dev generated from your seed.
           *
           * @dev The requestId argument is generated from the keyHash and the seed by
           * @dev makeRequestId(keyHash, seed). If your contract could have concurrent
           * @dev requests open, you can use the requestId to track which seed is
           * @dev associated with which randomness. See VRFRequestIDBase.sol for more
           * @dev details. (See "SECURITY CONSIDERATIONS" for principles to keep in mind,
           * @dev if your contract could have multiple requests in flight simultaneously.)
           *
           * @dev Colliding `requestId`s are cryptographically impossible as long as seeds
           * @dev differ. (Which is critical to making unpredictable randomness! See the
           * @dev next section.)
           *
           * *****************************************************************************
           * @dev SECURITY CONSIDERATIONS
           *
           * @dev A method with the ability to call your fulfillRandomness method directly
           * @dev could spoof a VRF response with any random value, so it's critical that
           * @dev it cannot be directly called by anything other than this base contract
           * @dev (specifically, by the VRFConsumerBase.rawFulfillRandomness method).
           *
           * @dev For your users to trust that your contract's random behavior is free
           * @dev from malicious interference, it's best if you can write it so that all
           * @dev behaviors implied by a VRF response are executed *during* your
           * @dev fulfillRandomness method. If your contract must store the response (or
           * @dev anything derived from it) and use it later, you must ensure that any
           * @dev user-significant behavior which depends on that stored value cannot be
           * @dev manipulated by a subsequent VRF request.
           *
           * @dev Similarly, both miners and the VRF oracle itself have some influence
           * @dev over the order in which VRF responses appear on the blockchain, so if
           * @dev your contract could have multiple VRF requests in flight simultaneously,
           * @dev you must ensure that the order in which the VRF responses arrive cannot
           * @dev be used to manipulate your contract's user-significant behavior.
           *
           * @dev Since the ultimate input to the VRF is mixed with the block hash of the
           * @dev block in which the request is made, user-provided seeds have no impact
           * @dev on its economic security properties. They are only included for API
           * @dev compatability with previous versions of this contract.
           *
           * @dev Since the block hash of the block which contains the requestRandomness
           * @dev call is mixed into the input to the VRF *last*, a sufficiently powerful
           * @dev miner could, in principle, fork the blockchain to evict the block
           * @dev containing the request, forcing the request to be included in a
           * @dev different block with a different hash, and therefore a different input
           * @dev to the VRF. However, such an attack would incur a substantial economic
           * @dev cost. This cost scales with the number of blocks the VRF oracle waits
           * @dev until it calls responds to a request.
           */
          abstract contract VRFConsumerBase is VRFRequestIDBase {
            /**
             * @notice fulfillRandomness handles the VRF response. Your contract must
             * @notice implement it. See "SECURITY CONSIDERATIONS" above for important
             * @notice principles to keep in mind when implementing your fulfillRandomness
             * @notice method.
             *
             * @dev VRFConsumerBase expects its subcontracts to have a method with this
             * @dev signature, and will call it once it has verified the proof
             * @dev associated with the randomness. (It is triggered via a call to
             * @dev rawFulfillRandomness, below.)
             *
             * @param requestId The Id initially returned by requestRandomness
             * @param randomness the VRF output
             */
            function fulfillRandomness(bytes32 requestId, uint256 randomness) internal virtual;
            /**
             * @dev In order to keep backwards compatibility we have kept the user
             * seed field around. We remove the use of it because given that the blockhash
             * enters later, it overrides whatever randomness the used seed provides.
             * Given that it adds no security, and can easily lead to misunderstandings,
             * we have removed it from usage and can now provide a simpler API.
             */
            uint256 private constant USER_SEED_PLACEHOLDER = 0;
            /**
             * @notice requestRandomness initiates a request for VRF output given _seed
             *
             * @dev The fulfillRandomness method receives the output, once it's provided
             * @dev by the Oracle, and verified by the vrfCoordinator.
             *
             * @dev The _keyHash must already be registered with the VRFCoordinator, and
             * @dev the _fee must exceed the fee specified during registration of the
             * @dev _keyHash.
             *
             * @dev The _seed parameter is vestigial, and is kept only for API
             * @dev compatibility with older versions. It can't *hurt* to mix in some of
             * @dev your own randomness, here, but it's not necessary because the VRF
             * @dev oracle will mix the hash of the block containing your request into the
             * @dev VRF seed it ultimately uses.
             *
             * @param _keyHash ID of public key against which randomness is generated
             * @param _fee The amount of LINK to send with the request
             *
             * @return requestId unique ID for this request
             *
             * @dev The returned requestId can be used to distinguish responses to
             * @dev concurrent requests. It is passed as the first argument to
             * @dev fulfillRandomness.
             */
            function requestRandomness(bytes32 _keyHash, uint256 _fee) internal returns (bytes32 requestId) {
              LINK.transferAndCall(vrfCoordinator, _fee, abi.encode(_keyHash, USER_SEED_PLACEHOLDER));
              // This is the seed passed to VRFCoordinator. The oracle will mix this with
              // the hash of the block containing this request to obtain the seed/input
              // which is finally passed to the VRF cryptographic machinery.
              uint256 vRFSeed = makeVRFInputSeed(_keyHash, USER_SEED_PLACEHOLDER, address(this), nonces[_keyHash]);
              // nonces[_keyHash] must stay in sync with
              // VRFCoordinator.nonces[_keyHash][this], which was incremented by the above
              // successful LINK.transferAndCall (in VRFCoordinator.randomnessRequest).
              // This provides protection against the user repeating their input seed,
              // which would result in a predictable/duplicate output, if multiple such
              // requests appeared in the same block.
              nonces[_keyHash] = nonces[_keyHash] + 1;
              return makeRequestId(_keyHash, vRFSeed);
            }
            LinkTokenInterface internal immutable LINK;
            address private immutable vrfCoordinator;
            // Nonces for each VRF key from which randomness has been requested.
            //
            // Must stay in sync with VRFCoordinator[_keyHash][this]
            mapping(bytes32 => uint256) /* keyHash */ /* nonce */
              private nonces;
            /**
             * @param _vrfCoordinator address of VRFCoordinator contract
             * @param _link address of LINK token contract
             *
             * @dev https://docs.chain.link/docs/link-token-contracts
             */
            constructor(address _vrfCoordinator, address _link) {
              vrfCoordinator = _vrfCoordinator;
              LINK = LinkTokenInterface(_link);
            }
            // rawFulfillRandomness is called by VRFCoordinator when it receives a valid VRF
            // proof. rawFulfillRandomness then calls fulfillRandomness, after validating
            // the origin of the call
            function rawFulfillRandomness(bytes32 requestId, uint256 randomness) external {
              require(msg.sender == vrfCoordinator, "Only VRFCoordinator can fulfill");
              fulfillRandomness(requestId, randomness);
            }
          }
          

          File 4 of 8: BlurExchange
          // SPDX-License-Identifier: MIT
          pragma solidity 0.8.17;
          import "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";
          import "@openzeppelin/contracts-upgradeable/proxy/utils/UUPSUpgradeable.sol";
          import "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";
          import "./lib/ReentrancyGuarded.sol";
          import "./lib/EIP712.sol";
          import "./lib/MerkleVerifier.sol";
          import "./interfaces/IBlurExchange.sol";
          import "./interfaces/IBlurPool.sol";
          import "./interfaces/IExecutionDelegate.sol";
          import "./interfaces/IPolicyManager.sol";
          import "./interfaces/IMatchingPolicy.sol";
          import {
            Side,
            SignatureVersion,
            AssetType,
            Fee,
            Order,
            Input,
            Execution
          } from "./lib/OrderStructs.sol";
          /**
           * @title BlurExchange
           * @dev Core Blur exchange contract
           */
          contract BlurExchange is IBlurExchange, ReentrancyGuarded, EIP712, OwnableUpgradeable, UUPSUpgradeable {
              /* Auth */
              uint256 public isOpen;
              modifier whenOpen() {
                  require(isOpen == 1, "Closed");
                  _;
              }
              modifier setupExecution() {
                  require(!isInternal, "Unsafe call"); // add redundant re-entrancy check for clarity
                  remainingETH = msg.value;
                  isInternal = true;
                  _;
                  remainingETH = 0;
                  isInternal = false;
              }
              modifier internalCall() {
                  require(isInternal, "Unsafe call");
                  _;
              }
              event Opened();
              event Closed();
              function open() external onlyOwner {
                  isOpen = 1;
                  emit Opened();
              }
              function close() external onlyOwner {
                  isOpen = 0;
                  emit Closed();
              }
              // required by the OZ UUPS module
              function _authorizeUpgrade(address) internal override onlyOwner {}
              /* Constants */
              string public constant NAME = "Blur Exchange";
              string public constant VERSION = "1.0";
              uint256 public constant INVERSE_BASIS_POINT = 10_000;
              address public constant WETH = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;
              address public constant POOL = 0x0000000000A39bb272e79075ade125fd351887Ac;
              /* Variables */
              IExecutionDelegate public executionDelegate;
              IPolicyManager public policyManager;
              address public oracle;
              uint256 public blockRange;
              /* Storage */
              mapping(bytes32 => bool) public cancelledOrFilled;
              mapping(address => uint256) public nonces;
              /* Events */
              event OrdersMatched(
                  address indexed maker,
                  address indexed taker,
                  Order sell,
                  bytes32 sellHash,
                  Order buy,
                  bytes32 buyHash
              );
              event OrderCancelled(bytes32 hash);
              event NonceIncremented(address indexed trader, uint256 newNonce);
              event NewExecutionDelegate(IExecutionDelegate indexed executionDelegate);
              event NewPolicyManager(IPolicyManager indexed policyManager);
              event NewOracle(address indexed oracle);
              event NewBlockRange(uint256 blockRange);
              constructor() {
                _disableInitializers();
              }
              /* Constructor (for ERC1967) */
              function initialize(
                  IExecutionDelegate _executionDelegate,
                  IPolicyManager _policyManager,
                  address _oracle,
                  uint _blockRange
              ) external initializer {
                  __Ownable_init();
                  isOpen = 1;
                  DOMAIN_SEPARATOR = _hashDomain(EIP712Domain({
                      name              : NAME,
                      version           : VERSION,
                      chainId           : block.chainid,
                      verifyingContract : address(this)
                  }));
                  executionDelegate = _executionDelegate;
                  policyManager = _policyManager;
                  oracle = _oracle;
                  blockRange = _blockRange;
              }
              /* External Functions */
              bool public isInternal = false;
              uint256 public remainingETH = 0;
              /**
               * @dev _execute wrapper
               * @param sell Sell input
               * @param buy Buy input
               */
              function execute(Input calldata sell, Input calldata buy)
                  external
                  payable
                  whenOpen
                  setupExecution
              {
                  _execute(sell, buy);
                  _returnDust();
              }
              /**
               * @dev Bulk execute multiple matches
               * @param executions Potential buy/sell matches
               */
              function bulkExecute(Execution[] calldata executions)
                  external
                  payable
                  whenOpen
                  setupExecution
              {
                  /*
                  REFERENCE
                  uint256 executionsLength = executions.length;
                  for (uint8 i=0; i < executionsLength; i++) {
                      bytes memory data = abi.encodeWithSelector(this._execute.selector, executions[i].sell, executions[i].buy);
                      (bool success,) = address(this).delegatecall(data);
                  }
                  _returnDust(remainingETH);
                  */
                  uint256 executionsLength = executions.length;
                  if (executionsLength == 0) {
                    revert("No orders to execute");
                  }
                  for (uint8 i = 0; i < executionsLength; i++) {
                      assembly {
                          let memPointer := mload(0x40)
                          let order_location := calldataload(add(executions.offset, mul(i, 0x20)))
                          let order_pointer := add(executions.offset, order_location)
                          let size
                          switch eq(add(i, 0x01), executionsLength)
                          case 1 {
                              size := sub(calldatasize(), order_pointer)
                          }
                          default {
                              let next_order_location := calldataload(add(executions.offset, mul(add(i, 0x01), 0x20)))
                              let next_order_pointer := add(executions.offset, next_order_location)
                              size := sub(next_order_pointer, order_pointer)
                          }
                          mstore(memPointer, 0xe04d94ae00000000000000000000000000000000000000000000000000000000) // _execute
                          calldatacopy(add(0x04, memPointer), order_pointer, size)
                          // must be put in separate transaction to bypass failed executions
                          // must be put in delegatecall to maintain the authorization from the caller
                          let result := delegatecall(gas(), address(), memPointer, add(size, 0x04), 0, 0)
                      }
                  }
                  _returnDust();
              }
              /**
               * @dev Match two orders, ensuring validity of the match, and execute all associated state transitions. Must be called internally.
               * @param sell Sell input
               * @param buy Buy input
               */
              function _execute(Input calldata sell, Input calldata buy)
                  public
                  payable
                  internalCall
                  reentrancyGuard // move re-entrancy check for clarity
              {
                  require(sell.order.side == Side.Sell);
                  bytes32 sellHash = _hashOrder(sell.order, nonces[sell.order.trader]);
                  bytes32 buyHash = _hashOrder(buy.order, nonces[buy.order.trader]);
                  require(_validateOrderParameters(sell.order, sellHash), "Sell has invalid parameters");
                  require(_validateOrderParameters(buy.order, buyHash), "Buy has invalid parameters");
                  require(_validateSignatures(sell, sellHash), "Sell failed authorization");
                  require(_validateSignatures(buy, buyHash), "Buy failed authorization");
                  (uint256 price, uint256 tokenId, uint256 amount, AssetType assetType) = _canMatchOrders(sell.order, buy.order);
                  /* Mark orders as filled. */
                  cancelledOrFilled[sellHash] = true;
                  cancelledOrFilled[buyHash] = true;
                  _executeFundsTransfer(
                      sell.order.trader,
                      buy.order.trader,
                      sell.order.paymentToken,
                      sell.order.fees,
                      price
                  );
                  _executeTokenTransfer(
                      sell.order.collection,
                      sell.order.trader,
                      buy.order.trader,
                      tokenId,
                      amount,
                      assetType
                  );
                  emit OrdersMatched(
                      sell.order.listingTime <= buy.order.listingTime ? sell.order.trader : buy.order.trader,
                      sell.order.listingTime > buy.order.listingTime ? sell.order.trader : buy.order.trader,
                      sell.order,
                      sellHash,
                      buy.order,
                      buyHash
                  );
              }
              /**
               * @dev Cancel an order, preventing it from being matched. Must be called by the trader of the order
               * @param order Order to cancel
               */
              function cancelOrder(Order calldata order) public {
                  /* Assert sender is authorized to cancel order. */
                  require(msg.sender == order.trader, "Not sent by trader");
                  bytes32 hash = _hashOrder(order, nonces[order.trader]);
                  require(!cancelledOrFilled[hash], "Order cancelled or filled");
                  /* Mark order as cancelled, preventing it from being matched. */
                  cancelledOrFilled[hash] = true;
                  emit OrderCancelled(hash);
              }
              /**
               * @dev Cancel multiple orders
               * @param orders Orders to cancel
               */
              function cancelOrders(Order[] calldata orders) external {
                  for (uint8 i = 0; i < orders.length; i++) {
                      cancelOrder(orders[i]);
                  }
              }
              /**
               * @dev Cancel all current orders for a user, preventing them from being matched. Must be called by the trader of the order
               */
              function incrementNonce() external {
                  nonces[msg.sender] += 1;
                  emit NonceIncremented(msg.sender, nonces[msg.sender]);
              }
              /* Setters */
              function setExecutionDelegate(IExecutionDelegate _executionDelegate)
                  external
                  onlyOwner
              {
                  require(address(_executionDelegate) != address(0), "Address cannot be zero");
                  executionDelegate = _executionDelegate;
                  emit NewExecutionDelegate(executionDelegate);
              }
              function setPolicyManager(IPolicyManager _policyManager)
                  external
                  onlyOwner
              {
                  require(address(_policyManager) != address(0), "Address cannot be zero");
                  policyManager = _policyManager;
                  emit NewPolicyManager(policyManager);
              }
              function setOracle(address _oracle)
                  external
                  onlyOwner
              {
                  require(_oracle != address(0), "Address cannot be zero");
                  oracle = _oracle;
                  emit NewOracle(oracle);
              }
              function setBlockRange(uint256 _blockRange)
                  external
                  onlyOwner
              {
                  blockRange = _blockRange;
                  emit NewBlockRange(blockRange);
              }
              /* Internal Functions */
              /**
               * @dev Verify the validity of the order parameters
               * @param order order
               * @param orderHash hash of order
               */
              function _validateOrderParameters(Order calldata order, bytes32 orderHash)
                  internal
                  view
                  returns (bool)
              {
                  return (
                      /* Order must have a trader. */
                      (order.trader != address(0)) &&
                      /* Order must not be cancelled or filled. */
                      (!cancelledOrFilled[orderHash]) &&
                      /* Order must be settleable. */
                      (order.listingTime < block.timestamp) &&
                      (block.timestamp < order.expirationTime)
                  );
              }
              /**
               * @dev Verify the validity of the signatures
               * @param order order
               * @param orderHash hash of order
               */
              function _validateSignatures(Input calldata order, bytes32 orderHash)
                  internal
                  view
                  returns (bool)
              {
                  if (order.order.extraParams.length > 0 && order.order.extraParams[0] == 0x01) {
                      /* Check oracle authorization. */
                      require(block.number - order.blockNumber < blockRange, "Signed block number out of range");
                      if (
                          !_validateOracleAuthorization(
                              orderHash,
                              order.signatureVersion,
                              order.extraSignature,
                              order.blockNumber
                          )
                      ) {
                          return false;
                      }
                  }
                  if (order.order.trader == msg.sender) {
                    return true;
                  }
                  /* Check user authorization. */
                  if (
                      !_validateUserAuthorization(
                          orderHash,
                          order.order.trader,
                          order.v,
                          order.r,
                          order.s,
                          order.signatureVersion,
                          order.extraSignature
                      )
                  ) {
                      return false;
                  }
                  return true;
              }
              /**
               * @dev Verify the validity of the user signature
               * @param orderHash hash of the order
               * @param trader order trader who should be the signer
               * @param v v
               * @param r r
               * @param s s
               * @param signatureVersion signature version
               * @param extraSignature packed merkle path
               */
              function _validateUserAuthorization(
                  bytes32 orderHash,
                  address trader,
                  uint8 v,
                  bytes32 r,
                  bytes32 s,
                  SignatureVersion signatureVersion,
                  bytes calldata extraSignature
              ) internal view returns (bool) {
                  bytes32 hashToSign;
                  if (signatureVersion == SignatureVersion.Single) {
                      /* Single-listing authentication: Order signed by trader */
                      hashToSign = _hashToSign(orderHash);
                  } else if (signatureVersion == SignatureVersion.Bulk) {
                      /* Bulk-listing authentication: Merkle root of orders signed by trader */
                      (bytes32[] memory merklePath) = abi.decode(extraSignature, (bytes32[]));
                      bytes32 computedRoot = MerkleVerifier._computeRoot(orderHash, merklePath);
                      hashToSign = _hashToSignRoot(computedRoot);
                  }
                  return _verify(trader, hashToSign, v, r, s);
              }
              /**
               * @dev Verify the validity of oracle signature
               * @param orderHash hash of the order
               * @param signatureVersion signature version
               * @param extraSignature packed oracle signature
               * @param blockNumber block number used in oracle signature
               */
              function _validateOracleAuthorization(
                  bytes32 orderHash,
                  SignatureVersion signatureVersion,
                  bytes calldata extraSignature,
                  uint256 blockNumber
              ) internal view returns (bool) {
                  bytes32 oracleHash = _hashToSignOracle(orderHash, blockNumber);
                  uint8 v; bytes32 r; bytes32 s;
                  if (signatureVersion == SignatureVersion.Single) {
                      assembly {
                          v := calldataload(extraSignature.offset)
                          r := calldataload(add(extraSignature.offset, 0x20))
                          s := calldataload(add(extraSignature.offset, 0x40))
                      }
                      /*
                      REFERENCE
                      (v, r, s) = abi.decode(extraSignature, (uint8, bytes32, bytes32));
                      */
                  } else if (signatureVersion == SignatureVersion.Bulk) {
                      /* If the signature was a bulk listing the merkle path must be unpacked before the oracle signature. */
                      assembly {
                          v := calldataload(add(extraSignature.offset, 0x20))
                          r := calldataload(add(extraSignature.offset, 0x40))
                          s := calldataload(add(extraSignature.offset, 0x60))
                      }
                      /*
                      REFERENCE
                      uint8 _v, bytes32 _r, bytes32 _s;
                      (bytes32[] memory merklePath, uint8 _v, bytes32 _r, bytes32 _s) = abi.decode(extraSignature, (bytes32[], uint8, bytes32, bytes32));
                      v = _v; r = _r; s = _s;
                      */
                  }
                  return _verify(oracle, oracleHash, v, r, s);
              }
              /**
               * @dev Verify ECDSA signature
               * @param signer Expected signer
               * @param digest Signature preimage
               * @param v v
               * @param r r
               * @param s s
               */
              function _verify(
                  address signer,
                  bytes32 digest,
                  uint8 v,
                  bytes32 r,
                  bytes32 s
              ) internal pure returns (bool) {
                  require(v == 27 || v == 28, "Invalid v parameter");
                  address recoveredSigner = ecrecover(digest, v, r, s);
                  if (recoveredSigner == address(0)) {
                    return false;
                  } else {
                    return signer == recoveredSigner;
                  }
              }
              /**
               * @dev Call the matching policy to check orders can be matched and get execution parameters
               * @param sell sell order
               * @param buy buy order
               */
              function _canMatchOrders(Order calldata sell, Order calldata buy)
                  internal
                  view
                  returns (uint256 price, uint256 tokenId, uint256 amount, AssetType assetType)
              {
                  bool canMatch;
                  if (sell.listingTime <= buy.listingTime) {
                      /* Seller is maker. */
                      require(policyManager.isPolicyWhitelisted(sell.matchingPolicy), "Policy is not whitelisted");
                      (canMatch, price, tokenId, amount, assetType) = IMatchingPolicy(sell.matchingPolicy).canMatchMakerAsk(sell, buy);
                  } else {
                      /* Buyer is maker. */
                      require(policyManager.isPolicyWhitelisted(buy.matchingPolicy), "Policy is not whitelisted");
                      (canMatch, price, tokenId, amount, assetType) = IMatchingPolicy(buy.matchingPolicy).canMatchMakerBid(buy, sell);
                  }
                  require(canMatch, "Orders cannot be matched");
                  return (price, tokenId, amount, assetType);
              }
              /**
               * @dev Execute all ERC20 token / ETH transfers associated with an order match (fees and buyer => seller transfer)
               * @param seller seller
               * @param buyer buyer
               * @param paymentToken payment token
               * @param fees fees
               * @param price price
               */
              function _executeFundsTransfer(
                  address seller,
                  address buyer,
                  address paymentToken,
                  Fee[] calldata fees,
                  uint256 price
              ) internal {
                  if (paymentToken == address(0)) {
                      require(msg.sender == buyer, "Cannot use ETH");
                      require(remainingETH >= price, "Insufficient value");
                      remainingETH -= price;
                  }
                  /* Take fee. */
                  uint256 receiveAmount = _transferFees(fees, paymentToken, buyer, price);
                  /* Transfer remainder to seller. */
                  _transferTo(paymentToken, buyer, seller, receiveAmount);
              }
              /**
               * @dev Charge a fee in ETH or WETH
               * @param fees fees to distribute
               * @param paymentToken address of token to pay in
               * @param from address to charge fees
               * @param price price of token
               */
              function _transferFees(
                  Fee[] calldata fees,
                  address paymentToken,
                  address from,
                  uint256 price
              ) internal returns (uint256) {
                  uint256 totalFee = 0;
                  for (uint8 i = 0; i < fees.length; i++) {
                      uint256 fee = (price * fees[i].rate) / INVERSE_BASIS_POINT;
                      _transferTo(paymentToken, from, fees[i].recipient, fee);
                      totalFee += fee;
                  }
                  require(totalFee <= price, "Fees are more than the price");
                  /* Amount that will be received by seller. */
                  uint256 receiveAmount = price - totalFee;
                  return (receiveAmount);
              }
              /**
               * @dev Transfer amount in ETH or WETH
               * @param paymentToken address of token to pay in
               * @param from token sender
               * @param to token recipient
               * @param amount amount to transfer
               */
              function _transferTo(
                  address paymentToken,
                  address from,
                  address to,
                  uint256 amount
              ) internal {
                  if (amount == 0) {
                      return;
                  }
                  if (paymentToken == address(0)) {
                      /* Transfer funds in ETH. */
                      require(to != address(0), "Transfer to zero address");
                      (bool success,) = payable(to).call{value: amount}("");
                      require(success, "ETH transfer failed");
                  } else if (paymentToken == POOL) {
                      /* Transfer Pool funds. */
                      bool success = IBlurPool(POOL).transferFrom(from, to, amount);
                      require(success, "Pool transfer failed");
                  } else if (paymentToken == WETH) {
                      /* Transfer funds in WETH. */
                      executionDelegate.transferERC20(WETH, from, to, amount);
                  } else {
                      revert("Invalid payment token");
                  }
              }
              /**
               * @dev Execute call through delegate proxy
               * @param collection collection contract address
               * @param from seller address
               * @param to buyer address
               * @param tokenId tokenId
               * @param assetType asset type of the token
               */
              function _executeTokenTransfer(
                  address collection,
                  address from,
                  address to,
                  uint256 tokenId,
                  uint256 amount,
                  AssetType assetType
              ) internal {
                  /* Call execution delegate. */
                  if (assetType == AssetType.ERC721) {
                      executionDelegate.transferERC721(collection, from, to, tokenId);
                  } else if (assetType == AssetType.ERC1155) {
                      executionDelegate.transferERC1155(collection, from, to, tokenId, amount);
                  }
              }
              /**
               * @dev Return remaining ETH sent to bulkExecute or execute
               */
              function _returnDust() private {
                  uint256 _remainingETH = remainingETH;
                  assembly {
                      if gt(_remainingETH, 0) {
                          let callStatus := call(
                              gas(),
                              caller(),
                              _remainingETH,
                              0,
                              0,
                              0,
                              0
                          )
                          if iszero(callStatus) {
                            revert(0, 0)
                          }
                      }
                  }
              }
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts (last updated v4.7.0) (proxy/utils/Initializable.sol)
          pragma solidity ^0.8.2;
          import "../../utils/AddressUpgradeable.sol";
          /**
           * @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
           * behind a proxy. Since proxied contracts do not make use of a constructor, it's common to move constructor logic to an
           * external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
           * function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
           *
           * The initialization functions use a version number. Once a version number is used, it is consumed and cannot be
           * reused. This mechanism prevents re-execution of each "step" but allows the creation of new initialization steps in
           * case an upgrade adds a module that needs to be initialized.
           *
           * For example:
           *
           * [.hljs-theme-light.nopadding]
           * ```
           * contract MyToken is ERC20Upgradeable {
           *     function initialize() initializer public {
           *         __ERC20_init("MyToken", "MTK");
           *     }
           * }
           * contract MyTokenV2 is MyToken, ERC20PermitUpgradeable {
           *     function initializeV2() reinitializer(2) public {
           *         __ERC20Permit_init("MyToken");
           *     }
           * }
           * ```
           *
           * TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
           * possible by providing the encoded function call as the `_data` argument to {ERC1967Proxy-constructor}.
           *
           * CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
           * that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
           *
           * [CAUTION]
           * ====
           * Avoid leaving a contract uninitialized.
           *
           * An uninitialized contract can be taken over by an attacker. This applies to both a proxy and its implementation
           * contract, which may impact the proxy. To prevent the implementation contract from being used, you should invoke
           * the {_disableInitializers} function in the constructor to automatically lock it when it is deployed:
           *
           * [.hljs-theme-light.nopadding]
           * ```
           * /// @custom:oz-upgrades-unsafe-allow constructor
           * constructor() {
           *     _disableInitializers();
           * }
           * ```
           * ====
           */
          abstract contract Initializable {
              /**
               * @dev Indicates that the contract has been initialized.
               * @custom:oz-retyped-from bool
               */
              uint8 private _initialized;
              /**
               * @dev Indicates that the contract is in the process of being initialized.
               */
              bool private _initializing;
              /**
               * @dev Triggered when the contract has been initialized or reinitialized.
               */
              event Initialized(uint8 version);
              /**
               * @dev A modifier that defines a protected initializer function that can be invoked at most once. In its scope,
               * `onlyInitializing` functions can be used to initialize parent contracts. Equivalent to `reinitializer(1)`.
               */
              modifier initializer() {
                  bool isTopLevelCall = !_initializing;
                  require(
                      (isTopLevelCall && _initialized < 1) || (!AddressUpgradeable.isContract(address(this)) && _initialized == 1),
                      "Initializable: contract is already initialized"
                  );
                  _initialized = 1;
                  if (isTopLevelCall) {
                      _initializing = true;
                  }
                  _;
                  if (isTopLevelCall) {
                      _initializing = false;
                      emit Initialized(1);
                  }
              }
              /**
               * @dev A modifier that defines a protected reinitializer function that can be invoked at most once, and only if the
               * contract hasn't been initialized to a greater version before. In its scope, `onlyInitializing` functions can be
               * used to initialize parent contracts.
               *
               * `initializer` is equivalent to `reinitializer(1)`, so a reinitializer may be used after the original
               * initialization step. This is essential to configure modules that are added through upgrades and that require
               * initialization.
               *
               * Note that versions can jump in increments greater than 1; this implies that if multiple reinitializers coexist in
               * a contract, executing them in the right order is up to the developer or operator.
               */
              modifier reinitializer(uint8 version) {
                  require(!_initializing && _initialized < version, "Initializable: contract is already initialized");
                  _initialized = version;
                  _initializing = true;
                  _;
                  _initializing = false;
                  emit Initialized(version);
              }
              /**
               * @dev Modifier to protect an initialization function so that it can only be invoked by functions with the
               * {initializer} and {reinitializer} modifiers, directly or indirectly.
               */
              modifier onlyInitializing() {
                  require(_initializing, "Initializable: contract is not initializing");
                  _;
              }
              /**
               * @dev Locks the contract, preventing any future reinitialization. This cannot be part of an initializer call.
               * Calling this in the constructor of a contract will prevent that contract from being initialized or reinitialized
               * to any version. It is recommended to use this to lock implementation contracts that are designed to be called
               * through proxies.
               */
              function _disableInitializers() internal virtual {
                  require(!_initializing, "Initializable: contract is initializing");
                  if (_initialized < type(uint8).max) {
                      _initialized = type(uint8).max;
                      emit Initialized(type(uint8).max);
                  }
              }
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts (last updated v4.5.0) (proxy/utils/UUPSUpgradeable.sol)
          pragma solidity ^0.8.0;
          import "../../interfaces/draft-IERC1822Upgradeable.sol";
          import "../ERC1967/ERC1967UpgradeUpgradeable.sol";
          import "./Initializable.sol";
          /**
           * @dev An upgradeability mechanism designed for UUPS proxies. The functions included here can perform an upgrade of an
           * {ERC1967Proxy}, when this contract is set as the implementation behind such a proxy.
           *
           * A security mechanism ensures that an upgrade does not turn off upgradeability accidentally, although this risk is
           * reinstated if the upgrade retains upgradeability but removes the security mechanism, e.g. by replacing
           * `UUPSUpgradeable` with a custom implementation of upgrades.
           *
           * The {_authorizeUpgrade} function must be overridden to include access restriction to the upgrade mechanism.
           *
           * _Available since v4.1._
           */
          abstract contract UUPSUpgradeable is Initializable, IERC1822ProxiableUpgradeable, ERC1967UpgradeUpgradeable {
              function __UUPSUpgradeable_init() internal onlyInitializing {
              }
              function __UUPSUpgradeable_init_unchained() internal onlyInitializing {
              }
              /// @custom:oz-upgrades-unsafe-allow state-variable-immutable state-variable-assignment
              address private immutable __self = address(this);
              /**
               * @dev Check that the execution is being performed through a delegatecall call and that the execution context is
               * a proxy contract with an implementation (as defined in ERC1967) pointing to self. This should only be the case
               * for UUPS and transparent proxies that are using the current contract as their implementation. Execution of a
               * function through ERC1167 minimal proxies (clones) would not normally pass this test, but is not guaranteed to
               * fail.
               */
              modifier onlyProxy() {
                  require(address(this) != __self, "Function must be called through delegatecall");
                  require(_getImplementation() == __self, "Function must be called through active proxy");
                  _;
              }
              /**
               * @dev Check that the execution is not being performed through a delegate call. This allows a function to be
               * callable on the implementing contract but not through proxies.
               */
              modifier notDelegated() {
                  require(address(this) == __self, "UUPSUpgradeable: must not be called through delegatecall");
                  _;
              }
              /**
               * @dev Implementation of the ERC1822 {proxiableUUID} function. This returns the storage slot used by the
               * implementation. It is used to validate that the this implementation remains valid after an upgrade.
               *
               * IMPORTANT: A proxy pointing at a proxiable contract should not be considered proxiable itself, because this risks
               * bricking a proxy that upgrades to it, by delegating to itself until out of gas. Thus it is critical that this
               * function revert if invoked through a proxy. This is guaranteed by the `notDelegated` modifier.
               */
              function proxiableUUID() external view virtual override notDelegated returns (bytes32) {
                  return _IMPLEMENTATION_SLOT;
              }
              /**
               * @dev Upgrade the implementation of the proxy to `newImplementation`.
               *
               * Calls {_authorizeUpgrade}.
               *
               * Emits an {Upgraded} event.
               */
              function upgradeTo(address newImplementation) external virtual onlyProxy {
                  _authorizeUpgrade(newImplementation);
                  _upgradeToAndCallUUPS(newImplementation, new bytes(0), false);
              }
              /**
               * @dev Upgrade the implementation of the proxy to `newImplementation`, and subsequently execute the function call
               * encoded in `data`.
               *
               * Calls {_authorizeUpgrade}.
               *
               * Emits an {Upgraded} event.
               */
              function upgradeToAndCall(address newImplementation, bytes memory data) external payable virtual onlyProxy {
                  _authorizeUpgrade(newImplementation);
                  _upgradeToAndCallUUPS(newImplementation, data, true);
              }
              /**
               * @dev Function that should revert when `msg.sender` is not authorized to upgrade the contract. Called by
               * {upgradeTo} and {upgradeToAndCall}.
               *
               * Normally, this function will use an xref:access.adoc[access control] modifier such as {Ownable-onlyOwner}.
               *
               * ```solidity
               * function _authorizeUpgrade(address) internal override onlyOwner {}
               * ```
               */
              function _authorizeUpgrade(address newImplementation) internal virtual;
              /**
               * @dev This empty reserved space is put in place to allow future versions to add new
               * variables without shifting down storage in the inheritance chain.
               * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
               */
              uint256[50] private __gap;
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)
          pragma solidity ^0.8.0;
          import "../utils/ContextUpgradeable.sol";
          import "../proxy/utils/Initializable.sol";
          /**
           * @dev Contract module which provides a basic access control mechanism, where
           * there is an account (an owner) that can be granted exclusive access to
           * specific functions.
           *
           * By default, the owner account will be the one that deploys the contract. This
           * can later be changed with {transferOwnership}.
           *
           * This module is used through inheritance. It will make available the modifier
           * `onlyOwner`, which can be applied to your functions to restrict their use to
           * the owner.
           */
          abstract contract OwnableUpgradeable is Initializable, ContextUpgradeable {
              address private _owner;
              event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
              /**
               * @dev Initializes the contract setting the deployer as the initial owner.
               */
              function __Ownable_init() internal onlyInitializing {
                  __Ownable_init_unchained();
              }
              function __Ownable_init_unchained() internal onlyInitializing {
                  _transferOwnership(_msgSender());
              }
              /**
               * @dev Throws if called by any account other than the owner.
               */
              modifier onlyOwner() {
                  _checkOwner();
                  _;
              }
              /**
               * @dev Returns the address of the current owner.
               */
              function owner() public view virtual returns (address) {
                  return _owner;
              }
              /**
               * @dev Throws if the sender is not the owner.
               */
              function _checkOwner() internal view virtual {
                  require(owner() == _msgSender(), "Ownable: caller is not the owner");
              }
              /**
               * @dev Leaves the contract without owner. It will not be possible to call
               * `onlyOwner` functions anymore. Can only be called by the current owner.
               *
               * NOTE: Renouncing ownership will leave the contract without an owner,
               * thereby removing any functionality that is only available to the owner.
               */
              function renounceOwnership() public virtual onlyOwner {
                  _transferOwnership(address(0));
              }
              /**
               * @dev Transfers ownership of the contract to a new account (`newOwner`).
               * Can only be called by the current owner.
               */
              function transferOwnership(address newOwner) public virtual onlyOwner {
                  require(newOwner != address(0), "Ownable: new owner is the zero address");
                  _transferOwnership(newOwner);
              }
              /**
               * @dev Transfers ownership of the contract to a new account (`newOwner`).
               * Internal function without access restriction.
               */
              function _transferOwnership(address newOwner) internal virtual {
                  address oldOwner = _owner;
                  _owner = newOwner;
                  emit OwnershipTransferred(oldOwner, newOwner);
              }
              /**
               * @dev This empty reserved space is put in place to allow future versions to add new
               * variables without shifting down storage in the inheritance chain.
               * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
               */
              uint256[49] private __gap;
          }
          // SPDX-License-Identifier: MIT
          pragma solidity 0.8.17;
          /**
           * @title ReentrancyGuarded
           * @dev Protections for reentrancy attacks
           */
          contract ReentrancyGuarded {
              bool private reentrancyLock = false;
              /* Prevent a contract function from being reentrant-called. */
              modifier reentrancyGuard {
                  require(!reentrancyLock, "Reentrancy detected");
                  reentrancyLock = true;
                  _;
                  reentrancyLock = false;
              }
              uint256[49] private __gap;
          }
          // SPDX-License-Identifier: MIT
          pragma solidity 0.8.17;
          import {Order, Fee} from "./OrderStructs.sol";
          /**
           * @title EIP712
           * @dev Contains all of the order hashing functions for EIP712 compliant signatures
           */
          contract EIP712 {
              struct EIP712Domain {
                  string  name;
                  string  version;
                  uint256 chainId;
                  address verifyingContract;
              }
              /* Order typehash for EIP 712 compatibility. */
              bytes32 constant public FEE_TYPEHASH = keccak256(
                  "Fee(uint16 rate,address recipient)"
              );
              bytes32 constant public ORDER_TYPEHASH = keccak256(
                  "Order(address trader,uint8 side,address matchingPolicy,address collection,uint256 tokenId,uint256 amount,address paymentToken,uint256 price,uint256 listingTime,uint256 expirationTime,Fee[] fees,uint256 salt,bytes extraParams,uint256 nonce)Fee(uint16 rate,address recipient)"
              );
              bytes32 constant public ORACLE_ORDER_TYPEHASH = keccak256(
                  "OracleOrder(Order order,uint256 blockNumber)Fee(uint16 rate,address recipient)Order(address trader,uint8 side,address matchingPolicy,address collection,uint256 tokenId,uint256 amount,address paymentToken,uint256 price,uint256 listingTime,uint256 expirationTime,Fee[] fees,uint256 salt,bytes extraParams,uint256 nonce)"
              );
              bytes32 constant public ROOT_TYPEHASH = keccak256(
                  "Root(bytes32 root)"
              );
              bytes32 constant EIP712DOMAIN_TYPEHASH = keccak256(
                  "EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"
              );
              bytes32 DOMAIN_SEPARATOR;
              function _hashDomain(EIP712Domain memory eip712Domain)
                  internal
                  pure
                  returns (bytes32)
              {
                  return keccak256(
                      abi.encode(
                          EIP712DOMAIN_TYPEHASH,
                          keccak256(bytes(eip712Domain.name)),
                          keccak256(bytes(eip712Domain.version)),
                          eip712Domain.chainId,
                          eip712Domain.verifyingContract
                      )
                  );
              }
              function _hashFee(Fee calldata fee)
                  internal 
                  pure
                  returns (bytes32)
              {
                  return keccak256(
                      abi.encode(
                          FEE_TYPEHASH,
                          fee.rate,
                          fee.recipient
                      )
                  );
              }
              function _packFees(Fee[] calldata fees)
                  internal
                  pure
                  returns (bytes32)
              {
                  bytes32[] memory feeHashes = new bytes32[](
                      fees.length
                  );
                  for (uint256 i = 0; i < fees.length; i++) {
                      feeHashes[i] = _hashFee(fees[i]);
                  }
                  return keccak256(abi.encodePacked(feeHashes));
              }
              function _hashOrder(Order calldata order, uint256 nonce)
                  internal
                  pure
                  returns (bytes32)
              {
                  return keccak256(
                      bytes.concat(
                          abi.encode(
                                ORDER_TYPEHASH,
                                order.trader,
                                order.side,
                                order.matchingPolicy,
                                order.collection,
                                order.tokenId,
                                order.amount,
                                order.paymentToken,
                                order.price,
                                order.listingTime,
                                order.expirationTime,
                                _packFees(order.fees),
                                order.salt,
                                keccak256(order.extraParams)
                          ),
                          abi.encode(nonce)
                      )
                  );
              }
              function _hashToSign(bytes32 orderHash)
                  internal
                  view
                  returns (bytes32 hash)
              {
                  return keccak256(abi.encodePacked(
                      "\\x19\\x01",
                      DOMAIN_SEPARATOR,
                      orderHash
                  ));
              }
              function _hashToSignRoot(bytes32 root)
                  internal
                  view
                  returns (bytes32 hash)
              {
                  return keccak256(abi.encodePacked(
                      "\\x19\\x01",
                      DOMAIN_SEPARATOR,
                      keccak256(abi.encode(
                          ROOT_TYPEHASH,
                          root
                      ))
                  ));
              }
              function _hashToSignOracle(bytes32 orderHash, uint256 blockNumber)
                  internal
                  view
                  returns (bytes32 hash)
              {
                  return keccak256(abi.encodePacked(
                      "\\x19\\x01",
                      DOMAIN_SEPARATOR,
                      keccak256(abi.encode(
                          ORACLE_ORDER_TYPEHASH,
                          orderHash,
                          blockNumber
                      ))
                  ));
              }
              uint256[44] private __gap;
          }
          // SPDX-License-Identifier: MIT
          pragma solidity 0.8.17;
          /**
           * @title MerkleVerifier
           * @dev Utility functions for Merkle tree computations
           */
          library MerkleVerifier {
              error InvalidProof();
              /**
               * @dev Verify the merkle proof
               * @param leaf leaf
               * @param root root
               * @param proof proof
               */
              function _verifyProof(
                  bytes32 leaf,
                  bytes32 root,
                  bytes32[] memory proof
              ) public pure {
                  bytes32 computedRoot = _computeRoot(leaf, proof);
                  if (computedRoot != root) {
                      revert InvalidProof();
                  }
              }
              /**
               * @dev Compute the merkle root
               * @param leaf leaf
               * @param proof proof
               */
              function _computeRoot(
                  bytes32 leaf,
                  bytes32[] memory proof
              ) public pure returns (bytes32) {
                  bytes32 computedHash = leaf;
                  for (uint256 i = 0; i < proof.length; i++) {
                      bytes32 proofElement = proof[i];
                      computedHash = _hashPair(computedHash, proofElement);
                  }
                  return computedHash;
              }
              function _hashPair(bytes32 a, bytes32 b) private pure returns (bytes32) {
                  return a < b ? _efficientHash(a, b) : _efficientHash(b, a);
              }
              function _efficientHash(
                  bytes32 a,
                  bytes32 b
              ) private pure returns (bytes32 value) {
                  assembly {
                      mstore(0x00, a)
                      mstore(0x20, b)
                      value := keccak256(0x00, 0x40)
                  }
              }
          }
          // SPDX-License-Identifier: MIT
          pragma solidity 0.8.17;
          import {Input, Order} from "../lib/OrderStructs.sol";
          import "./IExecutionDelegate.sol";
          import "./IPolicyManager.sol";
          interface IBlurExchange {
              function nonces(address) external view returns (uint256);
              function close() external;
              function initialize(
                  IExecutionDelegate _executionDelegate,
                  IPolicyManager _policyManager,
                  address _oracle,
                  uint _blockRange
              ) external;
              function setExecutionDelegate(IExecutionDelegate _executionDelegate) external;
              function setPolicyManager(IPolicyManager _policyManager) external;
              function setOracle(address _oracle) external;
              function setBlockRange(uint256 _blockRange) external;
              function cancelOrder(Order calldata order) external;
              function cancelOrders(Order[] calldata orders) external;
              function incrementNonce() external;
              function execute(Input calldata sell, Input calldata buy)
                  external
                  payable;
          }
          pragma solidity ^0.8.17;
          interface IBlurPool {
              event Transfer(address indexed from, address indexed to, uint256 amount);
              function totalSupply() external view returns (uint256);
              function balanceOf(address user) external view returns (uint256);
              function deposit() external payable;
              function withdraw(uint256) external;
              function transferFrom(address from, address to, uint256 amount)
                  external
                  returns (bool);
          }
          // SPDX-License-Identifier: MIT
          pragma solidity 0.8.17;
          interface IExecutionDelegate {
              function approveContract(address _contract) external;
              function denyContract(address _contract) external;
              function revokeApproval() external;
              function grantApproval() external;
              function transferERC721Unsafe(address collection, address from, address to, uint256 tokenId) external;
              function transferERC721(address collection, address from, address to, uint256 tokenId) external;
              function transferERC1155(address collection, address from, address to, uint256 tokenId, uint256 amount) external;
              function transferERC20(address token, address from, address to, uint256 amount) external;
          }
          // SPDX-License-Identifier: MIT
          pragma solidity 0.8.17;
          interface IPolicyManager {
              function addPolicy(address policy) external;
              function removePolicy(address policy) external;
              function isPolicyWhitelisted(address policy) external view returns (bool);
              function viewWhitelistedPolicies(uint256 cursor, uint256 size) external view returns (address[] memory, uint256);
              function viewCountWhitelistedPolicies() external view returns (uint256);
          }
          // SPDX-License-Identifier: MIT
          pragma solidity 0.8.17;
          import {Order, AssetType} from "../lib/OrderStructs.sol";
          interface IMatchingPolicy {
              function canMatchMakerAsk(Order calldata makerAsk, Order calldata takerBid)
                  external
                  view
                  returns (
                      bool,
                      uint256,
                      uint256,
                      uint256,
                      AssetType
                  );
              function canMatchMakerBid(Order calldata makerBid, Order calldata takerAsk)
                  external
                  view
                  returns (
                      bool,
                      uint256,
                      uint256,
                      uint256,
                      AssetType
                  );
          }
          // SPDX-License-Identifier: MIT
          pragma solidity 0.8.17;
          enum Side { Buy, Sell }
          enum SignatureVersion { Single, Bulk }
          enum AssetType { ERC721, ERC1155 }
          struct Fee {
              uint16 rate;
              address payable recipient;
          }
          struct Order {
              address trader;
              Side side;
              address matchingPolicy;
              address collection;
              uint256 tokenId;
              uint256 amount;
              address paymentToken;
              uint256 price;
              uint256 listingTime;
              /* Order expiration timestamp - 0 for oracle cancellations. */
              uint256 expirationTime;
              Fee[] fees;
              uint256 salt;
              bytes extraParams;
          }
          struct Input {
              Order order;
              uint8 v;
              bytes32 r;
              bytes32 s;
              bytes extraSignature;
              SignatureVersion signatureVersion;
              uint256 blockNumber;
          }
          struct Execution {
            Input sell;
            Input buy;
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts (last updated v4.7.0) (utils/Address.sol)
          pragma solidity ^0.8.1;
          /**
           * @dev Collection of functions related to the address type
           */
          library AddressUpgradeable {
              /**
               * @dev Returns true if `account` is a contract.
               *
               * [IMPORTANT]
               * ====
               * It is unsafe to assume that an address for which this function returns
               * false is an externally-owned account (EOA) and not a contract.
               *
               * Among others, `isContract` will return false for the following
               * types of addresses:
               *
               *  - an externally-owned account
               *  - a contract in construction
               *  - an address where a contract will be created
               *  - an address where a contract lived, but was destroyed
               * ====
               *
               * [IMPORTANT]
               * ====
               * You shouldn't rely on `isContract` to protect against flash loan attacks!
               *
               * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
               * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
               * constructor.
               * ====
               */
              function isContract(address account) internal view returns (bool) {
                  // This method relies on extcodesize/address.code.length, which returns 0
                  // for contracts in construction, since the code is only stored at the end
                  // of the constructor execution.
                  return account.code.length > 0;
              }
              /**
               * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
               * `recipient`, forwarding all available gas and reverting on errors.
               *
               * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
               * of certain opcodes, possibly making contracts go over the 2300 gas limit
               * imposed by `transfer`, making them unable to receive funds via
               * `transfer`. {sendValue} removes this limitation.
               *
               * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
               *
               * IMPORTANT: because control is transferred to `recipient`, care must be
               * taken to not create reentrancy vulnerabilities. Consider using
               * {ReentrancyGuard} or the
               * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
               */
              function sendValue(address payable recipient, uint256 amount) internal {
                  require(address(this).balance >= amount, "Address: insufficient balance");
                  (bool success, ) = recipient.call{value: amount}("");
                  require(success, "Address: unable to send value, recipient may have reverted");
              }
              /**
               * @dev Performs a Solidity function call using a low level `call`. A
               * plain `call` is an unsafe replacement for a function call: use this
               * function instead.
               *
               * If `target` reverts with a revert reason, it is bubbled up by this
               * function (like regular Solidity function calls).
               *
               * Returns the raw returned data. To convert to the expected return value,
               * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
               *
               * Requirements:
               *
               * - `target` must be a contract.
               * - calling `target` with `data` must not revert.
               *
               * _Available since v3.1._
               */
              function functionCall(address target, bytes memory data) internal returns (bytes memory) {
                  return functionCall(target, data, "Address: low-level call failed");
              }
              /**
               * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
               * `errorMessage` as a fallback revert reason when `target` reverts.
               *
               * _Available since v3.1._
               */
              function functionCall(
                  address target,
                  bytes memory data,
                  string memory errorMessage
              ) internal returns (bytes memory) {
                  return functionCallWithValue(target, data, 0, errorMessage);
              }
              /**
               * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
               * but also transferring `value` wei to `target`.
               *
               * Requirements:
               *
               * - the calling contract must have an ETH balance of at least `value`.
               * - the called Solidity function must be `payable`.
               *
               * _Available since v3.1._
               */
              function functionCallWithValue(
                  address target,
                  bytes memory data,
                  uint256 value
              ) internal returns (bytes memory) {
                  return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
              }
              /**
               * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
               * with `errorMessage` as a fallback revert reason when `target` reverts.
               *
               * _Available since v3.1._
               */
              function functionCallWithValue(
                  address target,
                  bytes memory data,
                  uint256 value,
                  string memory errorMessage
              ) internal returns (bytes memory) {
                  require(address(this).balance >= value, "Address: insufficient balance for call");
                  require(isContract(target), "Address: call to non-contract");
                  (bool success, bytes memory returndata) = target.call{value: value}(data);
                  return verifyCallResult(success, returndata, errorMessage);
              }
              /**
               * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
               * but performing a static call.
               *
               * _Available since v3.3._
               */
              function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
                  return functionStaticCall(target, data, "Address: low-level static call failed");
              }
              /**
               * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
               * but performing a static call.
               *
               * _Available since v3.3._
               */
              function functionStaticCall(
                  address target,
                  bytes memory data,
                  string memory errorMessage
              ) internal view returns (bytes memory) {
                  require(isContract(target), "Address: static call to non-contract");
                  (bool success, bytes memory returndata) = target.staticcall(data);
                  return verifyCallResult(success, returndata, errorMessage);
              }
              /**
               * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
               * revert reason using the provided one.
               *
               * _Available since v4.3._
               */
              function verifyCallResult(
                  bool success,
                  bytes memory returndata,
                  string memory errorMessage
              ) internal pure returns (bytes memory) {
                  if (success) {
                      return returndata;
                  } else {
                      // Look for revert reason and bubble it up if present
                      if (returndata.length > 0) {
                          // The easiest way to bubble the revert reason is using memory via assembly
                          /// @solidity memory-safe-assembly
                          assembly {
                              let returndata_size := mload(returndata)
                              revert(add(32, returndata), returndata_size)
                          }
                      } else {
                          revert(errorMessage);
                      }
                  }
              }
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts (last updated v4.5.0) (interfaces/draft-IERC1822.sol)
          pragma solidity ^0.8.0;
          /**
           * @dev ERC1822: Universal Upgradeable Proxy Standard (UUPS) documents a method for upgradeability through a simplified
           * proxy whose upgrades are fully controlled by the current implementation.
           */
          interface IERC1822ProxiableUpgradeable {
              /**
               * @dev Returns the storage slot that the proxiable contract assumes is being used to store the implementation
               * address.
               *
               * IMPORTANT: A proxy pointing at a proxiable contract should not be considered proxiable itself, because this risks
               * bricking a proxy that upgrades to it, by delegating to itself until out of gas. Thus it is critical that this
               * function revert if invoked through a proxy.
               */
              function proxiableUUID() external view returns (bytes32);
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts (last updated v4.5.0) (proxy/ERC1967/ERC1967Upgrade.sol)
          pragma solidity ^0.8.2;
          import "../beacon/IBeaconUpgradeable.sol";
          import "../../interfaces/draft-IERC1822Upgradeable.sol";
          import "../../utils/AddressUpgradeable.sol";
          import "../../utils/StorageSlotUpgradeable.sol";
          import "../utils/Initializable.sol";
          /**
           * @dev This abstract contract provides getters and event emitting update functions for
           * https://eips.ethereum.org/EIPS/eip-1967[EIP1967] slots.
           *
           * _Available since v4.1._
           *
           * @custom:oz-upgrades-unsafe-allow delegatecall
           */
          abstract contract ERC1967UpgradeUpgradeable is Initializable {
              function __ERC1967Upgrade_init() internal onlyInitializing {
              }
              function __ERC1967Upgrade_init_unchained() internal onlyInitializing {
              }
              // This is the keccak-256 hash of "eip1967.proxy.rollback" subtracted by 1
              bytes32 private constant _ROLLBACK_SLOT = 0x4910fdfa16fed3260ed0e7147f7cc6da11a60208b5b9406d12a635614ffd9143;
              /**
               * @dev Storage slot with the address of the current implementation.
               * This is the keccak-256 hash of "eip1967.proxy.implementation" subtracted by 1, and is
               * validated in the constructor.
               */
              bytes32 internal constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;
              /**
               * @dev Emitted when the implementation is upgraded.
               */
              event Upgraded(address indexed implementation);
              /**
               * @dev Returns the current implementation address.
               */
              function _getImplementation() internal view returns (address) {
                  return StorageSlotUpgradeable.getAddressSlot(_IMPLEMENTATION_SLOT).value;
              }
              /**
               * @dev Stores a new address in the EIP1967 implementation slot.
               */
              function _setImplementation(address newImplementation) private {
                  require(AddressUpgradeable.isContract(newImplementation), "ERC1967: new implementation is not a contract");
                  StorageSlotUpgradeable.getAddressSlot(_IMPLEMENTATION_SLOT).value = newImplementation;
              }
              /**
               * @dev Perform implementation upgrade
               *
               * Emits an {Upgraded} event.
               */
              function _upgradeTo(address newImplementation) internal {
                  _setImplementation(newImplementation);
                  emit Upgraded(newImplementation);
              }
              /**
               * @dev Perform implementation upgrade with additional setup call.
               *
               * Emits an {Upgraded} event.
               */
              function _upgradeToAndCall(
                  address newImplementation,
                  bytes memory data,
                  bool forceCall
              ) internal {
                  _upgradeTo(newImplementation);
                  if (data.length > 0 || forceCall) {
                      _functionDelegateCall(newImplementation, data);
                  }
              }
              /**
               * @dev Perform implementation upgrade with security checks for UUPS proxies, and additional setup call.
               *
               * Emits an {Upgraded} event.
               */
              function _upgradeToAndCallUUPS(
                  address newImplementation,
                  bytes memory data,
                  bool forceCall
              ) internal {
                  // Upgrades from old implementations will perform a rollback test. This test requires the new
                  // implementation to upgrade back to the old, non-ERC1822 compliant, implementation. Removing
                  // this special case will break upgrade paths from old UUPS implementation to new ones.
                  if (StorageSlotUpgradeable.getBooleanSlot(_ROLLBACK_SLOT).value) {
                      _setImplementation(newImplementation);
                  } else {
                      try IERC1822ProxiableUpgradeable(newImplementation).proxiableUUID() returns (bytes32 slot) {
                          require(slot == _IMPLEMENTATION_SLOT, "ERC1967Upgrade: unsupported proxiableUUID");
                      } catch {
                          revert("ERC1967Upgrade: new implementation is not UUPS");
                      }
                      _upgradeToAndCall(newImplementation, data, forceCall);
                  }
              }
              /**
               * @dev Storage slot with the admin of the contract.
               * This is the keccak-256 hash of "eip1967.proxy.admin" subtracted by 1, and is
               * validated in the constructor.
               */
              bytes32 internal constant _ADMIN_SLOT = 0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103;
              /**
               * @dev Emitted when the admin account has changed.
               */
              event AdminChanged(address previousAdmin, address newAdmin);
              /**
               * @dev Returns the current admin.
               */
              function _getAdmin() internal view returns (address) {
                  return StorageSlotUpgradeable.getAddressSlot(_ADMIN_SLOT).value;
              }
              /**
               * @dev Stores a new address in the EIP1967 admin slot.
               */
              function _setAdmin(address newAdmin) private {
                  require(newAdmin != address(0), "ERC1967: new admin is the zero address");
                  StorageSlotUpgradeable.getAddressSlot(_ADMIN_SLOT).value = newAdmin;
              }
              /**
               * @dev Changes the admin of the proxy.
               *
               * Emits an {AdminChanged} event.
               */
              function _changeAdmin(address newAdmin) internal {
                  emit AdminChanged(_getAdmin(), newAdmin);
                  _setAdmin(newAdmin);
              }
              /**
               * @dev The storage slot of the UpgradeableBeacon contract which defines the implementation for this proxy.
               * This is bytes32(uint256(keccak256('eip1967.proxy.beacon')) - 1)) and is validated in the constructor.
               */
              bytes32 internal constant _BEACON_SLOT = 0xa3f0ad74e5423aebfd80d3ef4346578335a9a72aeaee59ff6cb3582b35133d50;
              /**
               * @dev Emitted when the beacon is upgraded.
               */
              event BeaconUpgraded(address indexed beacon);
              /**
               * @dev Returns the current beacon.
               */
              function _getBeacon() internal view returns (address) {
                  return StorageSlotUpgradeable.getAddressSlot(_BEACON_SLOT).value;
              }
              /**
               * @dev Stores a new beacon in the EIP1967 beacon slot.
               */
              function _setBeacon(address newBeacon) private {
                  require(AddressUpgradeable.isContract(newBeacon), "ERC1967: new beacon is not a contract");
                  require(
                      AddressUpgradeable.isContract(IBeaconUpgradeable(newBeacon).implementation()),
                      "ERC1967: beacon implementation is not a contract"
                  );
                  StorageSlotUpgradeable.getAddressSlot(_BEACON_SLOT).value = newBeacon;
              }
              /**
               * @dev Perform beacon upgrade with additional setup call. Note: This upgrades the address of the beacon, it does
               * not upgrade the implementation contained in the beacon (see {UpgradeableBeacon-_setImplementation} for that).
               *
               * Emits a {BeaconUpgraded} event.
               */
              function _upgradeBeaconToAndCall(
                  address newBeacon,
                  bytes memory data,
                  bool forceCall
              ) internal {
                  _setBeacon(newBeacon);
                  emit BeaconUpgraded(newBeacon);
                  if (data.length > 0 || forceCall) {
                      _functionDelegateCall(IBeaconUpgradeable(newBeacon).implementation(), data);
                  }
              }
              /**
               * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
               * but performing a delegate call.
               *
               * _Available since v3.4._
               */
              function _functionDelegateCall(address target, bytes memory data) private returns (bytes memory) {
                  require(AddressUpgradeable.isContract(target), "Address: delegate call to non-contract");
                  // solhint-disable-next-line avoid-low-level-calls
                  (bool success, bytes memory returndata) = target.delegatecall(data);
                  return AddressUpgradeable.verifyCallResult(success, returndata, "Address: low-level delegate call failed");
              }
              /**
               * @dev This empty reserved space is put in place to allow future versions to add new
               * variables without shifting down storage in the inheritance chain.
               * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
               */
              uint256[50] private __gap;
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts v4.4.1 (proxy/beacon/IBeacon.sol)
          pragma solidity ^0.8.0;
          /**
           * @dev This is the interface that {BeaconProxy} expects of its beacon.
           */
          interface IBeaconUpgradeable {
              /**
               * @dev Must return an address that can be used as a delegate call target.
               *
               * {BeaconProxy} will check that this address is a contract.
               */
              function implementation() external view returns (address);
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts (last updated v4.7.0) (utils/StorageSlot.sol)
          pragma solidity ^0.8.0;
          /**
           * @dev Library for reading and writing primitive types to specific storage slots.
           *
           * Storage slots are often used to avoid storage conflict when dealing with upgradeable contracts.
           * This library helps with reading and writing to such slots without the need for inline assembly.
           *
           * The functions in this library return Slot structs that contain a `value` member that can be used to read or write.
           *
           * Example usage to set ERC1967 implementation slot:
           * ```
           * contract ERC1967 {
           *     bytes32 internal constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;
           *
           *     function _getImplementation() internal view returns (address) {
           *         return StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value;
           *     }
           *
           *     function _setImplementation(address newImplementation) internal {
           *         require(Address.isContract(newImplementation), "ERC1967: new implementation is not a contract");
           *         StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value = newImplementation;
           *     }
           * }
           * ```
           *
           * _Available since v4.1 for `address`, `bool`, `bytes32`, and `uint256`._
           */
          library StorageSlotUpgradeable {
              struct AddressSlot {
                  address value;
              }
              struct BooleanSlot {
                  bool value;
              }
              struct Bytes32Slot {
                  bytes32 value;
              }
              struct Uint256Slot {
                  uint256 value;
              }
              /**
               * @dev Returns an `AddressSlot` with member `value` located at `slot`.
               */
              function getAddressSlot(bytes32 slot) internal pure returns (AddressSlot storage r) {
                  /// @solidity memory-safe-assembly
                  assembly {
                      r.slot := slot
                  }
              }
              /**
               * @dev Returns an `BooleanSlot` with member `value` located at `slot`.
               */
              function getBooleanSlot(bytes32 slot) internal pure returns (BooleanSlot storage r) {
                  /// @solidity memory-safe-assembly
                  assembly {
                      r.slot := slot
                  }
              }
              /**
               * @dev Returns an `Bytes32Slot` with member `value` located at `slot`.
               */
              function getBytes32Slot(bytes32 slot) internal pure returns (Bytes32Slot storage r) {
                  /// @solidity memory-safe-assembly
                  assembly {
                      r.slot := slot
                  }
              }
              /**
               * @dev Returns an `Uint256Slot` with member `value` located at `slot`.
               */
              function getUint256Slot(bytes32 slot) internal pure returns (Uint256Slot storage r) {
                  /// @solidity memory-safe-assembly
                  assembly {
                      r.slot := slot
                  }
              }
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
          pragma solidity ^0.8.0;
          import "../proxy/utils/Initializable.sol";
          /**
           * @dev Provides information about the current execution context, including the
           * sender of the transaction and its data. While these are generally available
           * via msg.sender and msg.data, they should not be accessed in such a direct
           * manner, since when dealing with meta-transactions the account sending and
           * paying for execution may not be the actual sender (as far as an application
           * is concerned).
           *
           * This contract is only required for intermediate, library-like contracts.
           */
          abstract contract ContextUpgradeable is Initializable {
              function __Context_init() internal onlyInitializing {
              }
              function __Context_init_unchained() internal onlyInitializing {
              }
              function _msgSender() internal view virtual returns (address) {
                  return msg.sender;
              }
              function _msgData() internal view virtual returns (bytes calldata) {
                  return msg.data;
              }
              /**
               * @dev This empty reserved space is put in place to allow future versions to add new
               * variables without shifting down storage in the inheritance chain.
               * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
               */
              uint256[50] private __gap;
          }
          

          File 5 of 8: PolicyManager
          // SPDX-License-Identifier: MIT
          pragma solidity 0.8.17;
          import {Ownable} from "@openzeppelin/contracts/access/Ownable.sol";
          import {EnumerableSet} from "@openzeppelin/contracts/utils/structs/EnumerableSet.sol";
          import {IPolicyManager} from "./interfaces/IPolicyManager.sol";
          /**
           * @title PolicyManager
           * @dev Manages the policy whitelist for the Blur exchange
           */
          contract PolicyManager is IPolicyManager, Ownable {
              using EnumerableSet for EnumerableSet.AddressSet;
              EnumerableSet.AddressSet private _whitelistedPolicies;
              event PolicyRemoved(address indexed policy);
              event PolicyWhitelisted(address indexed policy);
              /**
               * @notice Add matching policy
               * @param policy address of policy to add
               */
              function addPolicy(address policy) external override onlyOwner {
                  require(!_whitelistedPolicies.contains(policy), "Already whitelisted");
                  _whitelistedPolicies.add(policy);
                  emit PolicyWhitelisted(policy);
              }
              /**
               * @notice Remove matching policy
               * @param policy address of policy to remove
               */
              function removePolicy(address policy) external override onlyOwner {
                  require(_whitelistedPolicies.contains(policy), "Not whitelisted");
                  _whitelistedPolicies.remove(policy);
                  emit PolicyRemoved(policy);
              }
              /**
               * @notice Returns if a policy has been added
               * @param policy address of the policy to check
               */
              function isPolicyWhitelisted(address policy) external view override returns (bool) {
                  return _whitelistedPolicies.contains(policy);
              }
              /**
               * @notice View number of whitelisted policies
               */
              function viewCountWhitelistedPolicies() external view override returns (uint256) {
                  return _whitelistedPolicies.length();
              }
              /**
               * @notice See whitelisted policies
               * @param cursor cursor
               * @param size size
               */
              function viewWhitelistedPolicies(uint256 cursor, uint256 size)
                  external
                  view
                  override
                  returns (address[] memory, uint256)
              {
                  uint256 length = size;
                  if (length > _whitelistedPolicies.length() - cursor) {
                      length = _whitelistedPolicies.length() - cursor;
                  }
                  address[] memory whitelistedPolicies = new address[](length);
                  for (uint256 i = 0; i < length; i++) {
                      whitelistedPolicies[i] = _whitelistedPolicies.at(cursor + i);
                  }
                  return (whitelistedPolicies, cursor + length);
              }
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)
          pragma solidity ^0.8.0;
          import "../utils/Context.sol";
          /**
           * @dev Contract module which provides a basic access control mechanism, where
           * there is an account (an owner) that can be granted exclusive access to
           * specific functions.
           *
           * By default, the owner account will be the one that deploys the contract. This
           * can later be changed with {transferOwnership}.
           *
           * This module is used through inheritance. It will make available the modifier
           * `onlyOwner`, which can be applied to your functions to restrict their use to
           * the owner.
           */
          abstract contract Ownable is Context {
              address private _owner;
              event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
              /**
               * @dev Initializes the contract setting the deployer as the initial owner.
               */
              constructor() {
                  _transferOwnership(_msgSender());
              }
              /**
               * @dev Returns the address of the current owner.
               */
              function owner() public view virtual returns (address) {
                  return _owner;
              }
              /**
               * @dev Throws if called by any account other than the owner.
               */
              modifier onlyOwner() {
                  require(owner() == _msgSender(), "Ownable: caller is not the owner");
                  _;
              }
              /**
               * @dev Leaves the contract without owner. It will not be possible to call
               * `onlyOwner` functions anymore. Can only be called by the current owner.
               *
               * NOTE: Renouncing ownership will leave the contract without an owner,
               * thereby removing any functionality that is only available to the owner.
               */
              function renounceOwnership() public virtual onlyOwner {
                  _transferOwnership(address(0));
              }
              /**
               * @dev Transfers ownership of the contract to a new account (`newOwner`).
               * Can only be called by the current owner.
               */
              function transferOwnership(address newOwner) public virtual onlyOwner {
                  require(newOwner != address(0), "Ownable: new owner is the zero address");
                  _transferOwnership(newOwner);
              }
              /**
               * @dev Transfers ownership of the contract to a new account (`newOwner`).
               * Internal function without access restriction.
               */
              function _transferOwnership(address newOwner) internal virtual {
                  address oldOwner = _owner;
                  _owner = newOwner;
                  emit OwnershipTransferred(oldOwner, newOwner);
              }
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts v4.4.1 (utils/structs/EnumerableSet.sol)
          pragma solidity ^0.8.0;
          /**
           * @dev Library for managing
           * https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive
           * types.
           *
           * Sets have the following properties:
           *
           * - Elements are added, removed, and checked for existence in constant time
           * (O(1)).
           * - Elements are enumerated in O(n). No guarantees are made on the ordering.
           *
           * ```
           * contract Example {
           *     // Add the library methods
           *     using EnumerableSet for EnumerableSet.AddressSet;
           *
           *     // Declare a set state variable
           *     EnumerableSet.AddressSet private mySet;
           * }
           * ```
           *
           * As of v3.3.0, sets of type `bytes32` (`Bytes32Set`), `address` (`AddressSet`)
           * and `uint256` (`UintSet`) are supported.
           */
          library EnumerableSet {
              // To implement this library for multiple types with as little code
              // repetition as possible, we write it in terms of a generic Set type with
              // bytes32 values.
              // The Set implementation uses private functions, and user-facing
              // implementations (such as AddressSet) are just wrappers around the
              // underlying Set.
              // This means that we can only create new EnumerableSets for types that fit
              // in bytes32.
              struct Set {
                  // Storage of set values
                  bytes32[] _values;
                  // Position of the value in the `values` array, plus 1 because index 0
                  // means a value is not in the set.
                  mapping(bytes32 => uint256) _indexes;
              }
              /**
               * @dev Add a value to a set. O(1).
               *
               * Returns true if the value was added to the set, that is if it was not
               * already present.
               */
              function _add(Set storage set, bytes32 value) private returns (bool) {
                  if (!_contains(set, value)) {
                      set._values.push(value);
                      // The value is stored at length-1, but we add 1 to all indexes
                      // and use 0 as a sentinel value
                      set._indexes[value] = set._values.length;
                      return true;
                  } else {
                      return false;
                  }
              }
              /**
               * @dev Removes a value from a set. O(1).
               *
               * Returns true if the value was removed from the set, that is if it was
               * present.
               */
              function _remove(Set storage set, bytes32 value) private returns (bool) {
                  // We read and store the value's index to prevent multiple reads from the same storage slot
                  uint256 valueIndex = set._indexes[value];
                  if (valueIndex != 0) {
                      // Equivalent to contains(set, value)
                      // To delete an element from the _values array in O(1), we swap the element to delete with the last one in
                      // the array, and then remove the last element (sometimes called as 'swap and pop').
                      // This modifies the order of the array, as noted in {at}.
                      uint256 toDeleteIndex = valueIndex - 1;
                      uint256 lastIndex = set._values.length - 1;
                      if (lastIndex != toDeleteIndex) {
                          bytes32 lastvalue = set._values[lastIndex];
                          // Move the last value to the index where the value to delete is
                          set._values[toDeleteIndex] = lastvalue;
                          // Update the index for the moved value
                          set._indexes[lastvalue] = valueIndex; // Replace lastvalue's index to valueIndex
                      }
                      // Delete the slot where the moved value was stored
                      set._values.pop();
                      // Delete the index for the deleted slot
                      delete set._indexes[value];
                      return true;
                  } else {
                      return false;
                  }
              }
              /**
               * @dev Returns true if the value is in the set. O(1).
               */
              function _contains(Set storage set, bytes32 value) private view returns (bool) {
                  return set._indexes[value] != 0;
              }
              /**
               * @dev Returns the number of values on the set. O(1).
               */
              function _length(Set storage set) private view returns (uint256) {
                  return set._values.length;
              }
              /**
               * @dev Returns the value stored at position `index` in the set. O(1).
               *
               * Note that there are no guarantees on the ordering of values inside the
               * array, and it may change when more values are added or removed.
               *
               * Requirements:
               *
               * - `index` must be strictly less than {length}.
               */
              function _at(Set storage set, uint256 index) private view returns (bytes32) {
                  return set._values[index];
              }
              /**
               * @dev Return the entire set in an array
               *
               * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
               * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
               * this function has an unbounded cost, and using it as part of a state-changing function may render the function
               * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
               */
              function _values(Set storage set) private view returns (bytes32[] memory) {
                  return set._values;
              }
              // Bytes32Set
              struct Bytes32Set {
                  Set _inner;
              }
              /**
               * @dev Add a value to a set. O(1).
               *
               * Returns true if the value was added to the set, that is if it was not
               * already present.
               */
              function add(Bytes32Set storage set, bytes32 value) internal returns (bool) {
                  return _add(set._inner, value);
              }
              /**
               * @dev Removes a value from a set. O(1).
               *
               * Returns true if the value was removed from the set, that is if it was
               * present.
               */
              function remove(Bytes32Set storage set, bytes32 value) internal returns (bool) {
                  return _remove(set._inner, value);
              }
              /**
               * @dev Returns true if the value is in the set. O(1).
               */
              function contains(Bytes32Set storage set, bytes32 value) internal view returns (bool) {
                  return _contains(set._inner, value);
              }
              /**
               * @dev Returns the number of values in the set. O(1).
               */
              function length(Bytes32Set storage set) internal view returns (uint256) {
                  return _length(set._inner);
              }
              /**
               * @dev Returns the value stored at position `index` in the set. O(1).
               *
               * Note that there are no guarantees on the ordering of values inside the
               * array, and it may change when more values are added or removed.
               *
               * Requirements:
               *
               * - `index` must be strictly less than {length}.
               */
              function at(Bytes32Set storage set, uint256 index) internal view returns (bytes32) {
                  return _at(set._inner, index);
              }
              /**
               * @dev Return the entire set in an array
               *
               * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
               * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
               * this function has an unbounded cost, and using it as part of a state-changing function may render the function
               * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
               */
              function values(Bytes32Set storage set) internal view returns (bytes32[] memory) {
                  return _values(set._inner);
              }
              // AddressSet
              struct AddressSet {
                  Set _inner;
              }
              /**
               * @dev Add a value to a set. O(1).
               *
               * Returns true if the value was added to the set, that is if it was not
               * already present.
               */
              function add(AddressSet storage set, address value) internal returns (bool) {
                  return _add(set._inner, bytes32(uint256(uint160(value))));
              }
              /**
               * @dev Removes a value from a set. O(1).
               *
               * Returns true if the value was removed from the set, that is if it was
               * present.
               */
              function remove(AddressSet storage set, address value) internal returns (bool) {
                  return _remove(set._inner, bytes32(uint256(uint160(value))));
              }
              /**
               * @dev Returns true if the value is in the set. O(1).
               */
              function contains(AddressSet storage set, address value) internal view returns (bool) {
                  return _contains(set._inner, bytes32(uint256(uint160(value))));
              }
              /**
               * @dev Returns the number of values in the set. O(1).
               */
              function length(AddressSet storage set) internal view returns (uint256) {
                  return _length(set._inner);
              }
              /**
               * @dev Returns the value stored at position `index` in the set. O(1).
               *
               * Note that there are no guarantees on the ordering of values inside the
               * array, and it may change when more values are added or removed.
               *
               * Requirements:
               *
               * - `index` must be strictly less than {length}.
               */
              function at(AddressSet storage set, uint256 index) internal view returns (address) {
                  return address(uint160(uint256(_at(set._inner, index))));
              }
              /**
               * @dev Return the entire set in an array
               *
               * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
               * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
               * this function has an unbounded cost, and using it as part of a state-changing function may render the function
               * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
               */
              function values(AddressSet storage set) internal view returns (address[] memory) {
                  bytes32[] memory store = _values(set._inner);
                  address[] memory result;
                  assembly {
                      result := store
                  }
                  return result;
              }
              // UintSet
              struct UintSet {
                  Set _inner;
              }
              /**
               * @dev Add a value to a set. O(1).
               *
               * Returns true if the value was added to the set, that is if it was not
               * already present.
               */
              function add(UintSet storage set, uint256 value) internal returns (bool) {
                  return _add(set._inner, bytes32(value));
              }
              /**
               * @dev Removes a value from a set. O(1).
               *
               * Returns true if the value was removed from the set, that is if it was
               * present.
               */
              function remove(UintSet storage set, uint256 value) internal returns (bool) {
                  return _remove(set._inner, bytes32(value));
              }
              /**
               * @dev Returns true if the value is in the set. O(1).
               */
              function contains(UintSet storage set, uint256 value) internal view returns (bool) {
                  return _contains(set._inner, bytes32(value));
              }
              /**
               * @dev Returns the number of values on the set. O(1).
               */
              function length(UintSet storage set) internal view returns (uint256) {
                  return _length(set._inner);
              }
              /**
               * @dev Returns the value stored at position `index` in the set. O(1).
               *
               * Note that there are no guarantees on the ordering of values inside the
               * array, and it may change when more values are added or removed.
               *
               * Requirements:
               *
               * - `index` must be strictly less than {length}.
               */
              function at(UintSet storage set, uint256 index) internal view returns (uint256) {
                  return uint256(_at(set._inner, index));
              }
              /**
               * @dev Return the entire set in an array
               *
               * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
               * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
               * this function has an unbounded cost, and using it as part of a state-changing function may render the function
               * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
               */
              function values(UintSet storage set) internal view returns (uint256[] memory) {
                  bytes32[] memory store = _values(set._inner);
                  uint256[] memory result;
                  assembly {
                      result := store
                  }
                  return result;
              }
          }
          // SPDX-License-Identifier: MIT
          pragma solidity 0.8.17;
          interface IPolicyManager {
              function addPolicy(address policy) external;
              function removePolicy(address policy) external;
              function isPolicyWhitelisted(address policy) external view returns (bool);
              function viewWhitelistedPolicies(uint256 cursor, uint256 size) external view returns (address[] memory, uint256);
              function viewCountWhitelistedPolicies() external view returns (uint256);
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
          pragma solidity ^0.8.0;
          /**
           * @dev Provides information about the current execution context, including the
           * sender of the transaction and its data. While these are generally available
           * via msg.sender and msg.data, they should not be accessed in such a direct
           * manner, since when dealing with meta-transactions the account sending and
           * paying for execution may not be the actual sender (as far as an application
           * is concerned).
           *
           * This contract is only required for intermediate, library-like contracts.
           */
          abstract contract Context {
              function _msgSender() internal view virtual returns (address) {
                  return msg.sender;
              }
              function _msgData() internal view virtual returns (bytes calldata) {
                  return msg.data;
              }
          }
          

          File 6 of 8: StandardPolicyERC721
          // SPDX-License-Identifier: MIT
          pragma solidity 0.8.17;
          import {Order, AssetType} from "../lib/OrderStructs.sol";
          import {IMatchingPolicy} from "../interfaces/IMatchingPolicy.sol";
          /**
           * @title StandardPolicyERC721
           * @dev Policy for matching orders at a fixed price for a specific ERC721 tokenId (requires oracle authorization on both orders)
           */
          contract StandardPolicyERC721 is IMatchingPolicy {
              function canMatchMakerAsk(Order calldata makerAsk, Order calldata takerBid)
                  external
                  pure
                  override
                  returns (
                      bool,
                      uint256,
                      uint256,
                      uint256,
                      AssetType
                  )
              {
                  return (
                      (makerAsk.side != takerBid.side) &&
                      (makerAsk.paymentToken == takerBid.paymentToken) &&
                      (makerAsk.collection == takerBid.collection) &&
                      (makerAsk.tokenId == takerBid.tokenId) &&
                      (makerAsk.extraParams.length > 0 && makerAsk.extraParams[0] == "\\x01") &&
                      (takerBid.extraParams.length > 0 && takerBid.extraParams[0] == "\\x01") &&
                      (makerAsk.amount == 1) &&
                      (takerBid.amount == 1) &&
                      (makerAsk.matchingPolicy == takerBid.matchingPolicy) &&
                      (makerAsk.price == takerBid.price),
                      makerAsk.price,
                      makerAsk.tokenId,
                      1,
                      AssetType.ERC721
                  );
              }
              function canMatchMakerBid(Order calldata makerBid, Order calldata takerAsk)
                  external
                  pure
                  override
                  returns (
                      bool,
                      uint256,
                      uint256,
                      uint256,
                      AssetType
                  )
              {
                  return (
                      (makerBid.side != takerAsk.side) &&
                      (makerBid.paymentToken == takerAsk.paymentToken) &&
                      (makerBid.collection == takerAsk.collection) &&
                      (makerBid.tokenId == takerAsk.tokenId) &&
                      (makerBid.extraParams.length > 0 && makerBid.extraParams[0] == "\\x01") &&
                      (takerAsk.extraParams.length > 0 && takerAsk.extraParams[0] == "\\x01") &&
                      (makerBid.amount == 1) &&
                      (takerAsk.amount == 1) &&
                      (makerBid.matchingPolicy == takerAsk.matchingPolicy) &&
                      (makerBid.price == takerAsk.price),
                      makerBid.price,
                      makerBid.tokenId,
                      1,
                      AssetType.ERC721
                  );
              }
          }
          // SPDX-License-Identifier: MIT
          pragma solidity 0.8.17;
          enum Side { Buy, Sell }
          enum SignatureVersion { Single, Bulk }
          enum AssetType { ERC721, ERC1155 }
          struct Fee {
              uint16 rate;
              address payable recipient;
          }
          struct Order {
              address trader;
              Side side;
              address matchingPolicy;
              address collection;
              uint256 tokenId;
              uint256 amount;
              address paymentToken;
              uint256 price;
              uint256 listingTime;
              /* Order expiration timestamp - 0 for oracle cancellations. */
              uint256 expirationTime;
              Fee[] fees;
              uint256 salt;
              bytes extraParams;
          }
          struct Input {
              Order order;
              uint8 v;
              bytes32 r;
              bytes32 s;
              bytes extraSignature;
              SignatureVersion signatureVersion;
              uint256 blockNumber;
          }
          struct Execution {
            Input sell;
            Input buy;
          }
          // SPDX-License-Identifier: MIT
          pragma solidity 0.8.17;
          import {Order, AssetType} from "../lib/OrderStructs.sol";
          interface IMatchingPolicy {
              function canMatchMakerAsk(Order calldata makerAsk, Order calldata takerBid)
                  external
                  view
                  returns (
                      bool,
                      uint256,
                      uint256,
                      uint256,
                      AssetType
                  );
              function canMatchMakerBid(Order calldata makerBid, Order calldata takerAsk)
                  external
                  view
                  returns (
                      bool,
                      uint256,
                      uint256,
                      uint256,
                      AssetType
                  );
          }
          

          File 7 of 8: GnosisSafe
          // SPDX-License-Identifier: LGPL-3.0-only
          pragma solidity >=0.7.0 <0.9.0;
          import "./base/ModuleManager.sol";
          import "./base/OwnerManager.sol";
          import "./base/FallbackManager.sol";
          import "./base/GuardManager.sol";
          import "./common/EtherPaymentFallback.sol";
          import "./common/Singleton.sol";
          import "./common/SignatureDecoder.sol";
          import "./common/SecuredTokenTransfer.sol";
          import "./common/StorageAccessible.sol";
          import "./interfaces/ISignatureValidator.sol";
          import "./external/GnosisSafeMath.sol";
          /// @title Gnosis Safe - A multisignature wallet with support for confirmations using signed messages based on ERC191.
          /// @author Stefan George - <[email protected]>
          /// @author Richard Meissner - <[email protected]>
          contract GnosisSafe is
              EtherPaymentFallback,
              Singleton,
              ModuleManager,
              OwnerManager,
              SignatureDecoder,
              SecuredTokenTransfer,
              ISignatureValidatorConstants,
              FallbackManager,
              StorageAccessible,
              GuardManager
          {
              using GnosisSafeMath for uint256;
              string public constant VERSION = "1.3.0";
              // keccak256(
              //     "EIP712Domain(uint256 chainId,address verifyingContract)"
              // );
              bytes32 private constant DOMAIN_SEPARATOR_TYPEHASH = 0x47e79534a245952e8b16893a336b85a3d9ea9fa8c573f3d803afb92a79469218;
              // keccak256(
              //     "SafeTx(address to,uint256 value,bytes data,uint8 operation,uint256 safeTxGas,uint256 baseGas,uint256 gasPrice,address gasToken,address refundReceiver,uint256 nonce)"
              // );
              bytes32 private constant SAFE_TX_TYPEHASH = 0xbb8310d486368db6bd6f849402fdd73ad53d316b5a4b2644ad6efe0f941286d8;
              event SafeSetup(address indexed initiator, address[] owners, uint256 threshold, address initializer, address fallbackHandler);
              event ApproveHash(bytes32 indexed approvedHash, address indexed owner);
              event SignMsg(bytes32 indexed msgHash);
              event ExecutionFailure(bytes32 txHash, uint256 payment);
              event ExecutionSuccess(bytes32 txHash, uint256 payment);
              uint256 public nonce;
              bytes32 private _deprecatedDomainSeparator;
              // Mapping to keep track of all message hashes that have been approve by ALL REQUIRED owners
              mapping(bytes32 => uint256) public signedMessages;
              // Mapping to keep track of all hashes (message or transaction) that have been approve by ANY owners
              mapping(address => mapping(bytes32 => uint256)) public approvedHashes;
              // This constructor ensures that this contract can only be used as a master copy for Proxy contracts
              constructor() {
                  // By setting the threshold it is not possible to call setup anymore,
                  // so we create a Safe with 0 owners and threshold 1.
                  // This is an unusable Safe, perfect for the singleton
                  threshold = 1;
              }
              /// @dev Setup function sets initial storage of contract.
              /// @param _owners List of Safe owners.
              /// @param _threshold Number of required confirmations for a Safe transaction.
              /// @param to Contract address for optional delegate call.
              /// @param data Data payload for optional delegate call.
              /// @param fallbackHandler Handler for fallback calls to this contract
              /// @param paymentToken Token that should be used for the payment (0 is ETH)
              /// @param payment Value that should be paid
              /// @param paymentReceiver Adddress that should receive the payment (or 0 if tx.origin)
              function setup(
                  address[] calldata _owners,
                  uint256 _threshold,
                  address to,
                  bytes calldata data,
                  address fallbackHandler,
                  address paymentToken,
                  uint256 payment,
                  address payable paymentReceiver
              ) external {
                  // setupOwners checks if the Threshold is already set, therefore preventing that this method is called twice
                  setupOwners(_owners, _threshold);
                  if (fallbackHandler != address(0)) internalSetFallbackHandler(fallbackHandler);
                  // As setupOwners can only be called if the contract has not been initialized we don't need a check for setupModules
                  setupModules(to, data);
                  if (payment > 0) {
                      // To avoid running into issues with EIP-170 we reuse the handlePayment function (to avoid adjusting code of that has been verified we do not adjust the method itself)
                      // baseGas = 0, gasPrice = 1 and gas = payment => amount = (payment + 0) * 1 = payment
                      handlePayment(payment, 0, 1, paymentToken, paymentReceiver);
                  }
                  emit SafeSetup(msg.sender, _owners, _threshold, to, fallbackHandler);
              }
              /// @dev Allows to execute a Safe transaction confirmed by required number of owners and then pays the account that submitted the transaction.
              ///      Note: The fees are always transferred, even if the user transaction fails.
              /// @param to Destination address of Safe transaction.
              /// @param value Ether value of Safe transaction.
              /// @param data Data payload of Safe transaction.
              /// @param operation Operation type of Safe transaction.
              /// @param safeTxGas Gas that should be used for the Safe transaction.
              /// @param baseGas Gas costs that are independent of the transaction execution(e.g. base transaction fee, signature check, payment of the refund)
              /// @param gasPrice Gas price that should be used for the payment calculation.
              /// @param gasToken Token address (or 0 if ETH) that is used for the payment.
              /// @param refundReceiver Address of receiver of gas payment (or 0 if tx.origin).
              /// @param signatures Packed signature data ({bytes32 r}{bytes32 s}{uint8 v})
              function execTransaction(
                  address to,
                  uint256 value,
                  bytes calldata data,
                  Enum.Operation operation,
                  uint256 safeTxGas,
                  uint256 baseGas,
                  uint256 gasPrice,
                  address gasToken,
                  address payable refundReceiver,
                  bytes memory signatures
              ) public payable virtual returns (bool success) {
                  bytes32 txHash;
                  // Use scope here to limit variable lifetime and prevent `stack too deep` errors
                  {
                      bytes memory txHashData =
                          encodeTransactionData(
                              // Transaction info
                              to,
                              value,
                              data,
                              operation,
                              safeTxGas,
                              // Payment info
                              baseGas,
                              gasPrice,
                              gasToken,
                              refundReceiver,
                              // Signature info
                              nonce
                          );
                      // Increase nonce and execute transaction.
                      nonce++;
                      txHash = keccak256(txHashData);
                      checkSignatures(txHash, txHashData, signatures);
                  }
                  address guard = getGuard();
                  {
                      if (guard != address(0)) {
                          Guard(guard).checkTransaction(
                              // Transaction info
                              to,
                              value,
                              data,
                              operation,
                              safeTxGas,
                              // Payment info
                              baseGas,
                              gasPrice,
                              gasToken,
                              refundReceiver,
                              // Signature info
                              signatures,
                              msg.sender
                          );
                      }
                  }
                  // We require some gas to emit the events (at least 2500) after the execution and some to perform code until the execution (500)
                  // We also include the 1/64 in the check that is not send along with a call to counteract potential shortings because of EIP-150
                  require(gasleft() >= ((safeTxGas * 64) / 63).max(safeTxGas + 2500) + 500, "GS010");
                  // Use scope here to limit variable lifetime and prevent `stack too deep` errors
                  {
                      uint256 gasUsed = gasleft();
                      // If the gasPrice is 0 we assume that nearly all available gas can be used (it is always more than safeTxGas)
                      // We only substract 2500 (compared to the 3000 before) to ensure that the amount passed is still higher than safeTxGas
                      success = execute(to, value, data, operation, gasPrice == 0 ? (gasleft() - 2500) : safeTxGas);
                      gasUsed = gasUsed.sub(gasleft());
                      // If no safeTxGas and no gasPrice was set (e.g. both are 0), then the internal tx is required to be successful
                      // This makes it possible to use `estimateGas` without issues, as it searches for the minimum gas where the tx doesn't revert
                      require(success || safeTxGas != 0 || gasPrice != 0, "GS013");
                      // We transfer the calculated tx costs to the tx.origin to avoid sending it to intermediate contracts that have made calls
                      uint256 payment = 0;
                      if (gasPrice > 0) {
                          payment = handlePayment(gasUsed, baseGas, gasPrice, gasToken, refundReceiver);
                      }
                      if (success) emit ExecutionSuccess(txHash, payment);
                      else emit ExecutionFailure(txHash, payment);
                  }
                  {
                      if (guard != address(0)) {
                          Guard(guard).checkAfterExecution(txHash, success);
                      }
                  }
              }
              function handlePayment(
                  uint256 gasUsed,
                  uint256 baseGas,
                  uint256 gasPrice,
                  address gasToken,
                  address payable refundReceiver
              ) private returns (uint256 payment) {
                  // solhint-disable-next-line avoid-tx-origin
                  address payable receiver = refundReceiver == address(0) ? payable(tx.origin) : refundReceiver;
                  if (gasToken == address(0)) {
                      // For ETH we will only adjust the gas price to not be higher than the actual used gas price
                      payment = gasUsed.add(baseGas).mul(gasPrice < tx.gasprice ? gasPrice : tx.gasprice);
                      require(receiver.send(payment), "GS011");
                  } else {
                      payment = gasUsed.add(baseGas).mul(gasPrice);
                      require(transferToken(gasToken, receiver, payment), "GS012");
                  }
              }
              /**
               * @dev Checks whether the signature provided is valid for the provided data, hash. Will revert otherwise.
               * @param dataHash Hash of the data (could be either a message hash or transaction hash)
               * @param data That should be signed (this is passed to an external validator contract)
               * @param signatures Signature data that should be verified. Can be ECDSA signature, contract signature (EIP-1271) or approved hash.
               */
              function checkSignatures(
                  bytes32 dataHash,
                  bytes memory data,
                  bytes memory signatures
              ) public view {
                  // Load threshold to avoid multiple storage loads
                  uint256 _threshold = threshold;
                  // Check that a threshold is set
                  require(_threshold > 0, "GS001");
                  checkNSignatures(dataHash, data, signatures, _threshold);
              }
              /**
               * @dev Checks whether the signature provided is valid for the provided data, hash. Will revert otherwise.
               * @param dataHash Hash of the data (could be either a message hash or transaction hash)
               * @param data That should be signed (this is passed to an external validator contract)
               * @param signatures Signature data that should be verified. Can be ECDSA signature, contract signature (EIP-1271) or approved hash.
               * @param requiredSignatures Amount of required valid signatures.
               */
              function checkNSignatures(
                  bytes32 dataHash,
                  bytes memory data,
                  bytes memory signatures,
                  uint256 requiredSignatures
              ) public view {
                  // Check that the provided signature data is not too short
                  require(signatures.length >= requiredSignatures.mul(65), "GS020");
                  // There cannot be an owner with address 0.
                  address lastOwner = address(0);
                  address currentOwner;
                  uint8 v;
                  bytes32 r;
                  bytes32 s;
                  uint256 i;
                  for (i = 0; i < requiredSignatures; i++) {
                      (v, r, s) = signatureSplit(signatures, i);
                      if (v == 0) {
                          // If v is 0 then it is a contract signature
                          // When handling contract signatures the address of the contract is encoded into r
                          currentOwner = address(uint160(uint256(r)));
                          // Check that signature data pointer (s) is not pointing inside the static part of the signatures bytes
                          // This check is not completely accurate, since it is possible that more signatures than the threshold are send.
                          // Here we only check that the pointer is not pointing inside the part that is being processed
                          require(uint256(s) >= requiredSignatures.mul(65), "GS021");
                          // Check that signature data pointer (s) is in bounds (points to the length of data -> 32 bytes)
                          require(uint256(s).add(32) <= signatures.length, "GS022");
                          // Check if the contract signature is in bounds: start of data is s + 32 and end is start + signature length
                          uint256 contractSignatureLen;
                          // solhint-disable-next-line no-inline-assembly
                          assembly {
                              contractSignatureLen := mload(add(add(signatures, s), 0x20))
                          }
                          require(uint256(s).add(32).add(contractSignatureLen) <= signatures.length, "GS023");
                          // Check signature
                          bytes memory contractSignature;
                          // solhint-disable-next-line no-inline-assembly
                          assembly {
                              // The signature data for contract signatures is appended to the concatenated signatures and the offset is stored in s
                              contractSignature := add(add(signatures, s), 0x20)
                          }
                          require(ISignatureValidator(currentOwner).isValidSignature(data, contractSignature) == EIP1271_MAGIC_VALUE, "GS024");
                      } else if (v == 1) {
                          // If v is 1 then it is an approved hash
                          // When handling approved hashes the address of the approver is encoded into r
                          currentOwner = address(uint160(uint256(r)));
                          // Hashes are automatically approved by the sender of the message or when they have been pre-approved via a separate transaction
                          require(msg.sender == currentOwner || approvedHashes[currentOwner][dataHash] != 0, "GS025");
                      } else if (v > 30) {
                          // If v > 30 then default va (27,28) has been adjusted for eth_sign flow
                          // To support eth_sign and similar we adjust v and hash the messageHash with the Ethereum message prefix before applying ecrecover
                          currentOwner = ecrecover(keccak256(abi.encodePacked("\\x19Ethereum Signed Message:\
          32", dataHash)), v - 4, r, s);
                      } else {
                          // Default is the ecrecover flow with the provided data hash
                          // Use ecrecover with the messageHash for EOA signatures
                          currentOwner = ecrecover(dataHash, v, r, s);
                      }
                      require(currentOwner > lastOwner && owners[currentOwner] != address(0) && currentOwner != SENTINEL_OWNERS, "GS026");
                      lastOwner = currentOwner;
                  }
              }
              /// @dev Allows to estimate a Safe transaction.
              ///      This method is only meant for estimation purpose, therefore the call will always revert and encode the result in the revert data.
              ///      Since the `estimateGas` function includes refunds, call this method to get an estimated of the costs that are deducted from the safe with `execTransaction`
              /// @param to Destination address of Safe transaction.
              /// @param value Ether value of Safe transaction.
              /// @param data Data payload of Safe transaction.
              /// @param operation Operation type of Safe transaction.
              /// @return Estimate without refunds and overhead fees (base transaction and payload data gas costs).
              /// @notice Deprecated in favor of common/StorageAccessible.sol and will be removed in next version.
              function requiredTxGas(
                  address to,
                  uint256 value,
                  bytes calldata data,
                  Enum.Operation operation
              ) external returns (uint256) {
                  uint256 startGas = gasleft();
                  // We don't provide an error message here, as we use it to return the estimate
                  require(execute(to, value, data, operation, gasleft()));
                  uint256 requiredGas = startGas - gasleft();
                  // Convert response to string and return via error message
                  revert(string(abi.encodePacked(requiredGas)));
              }
              /**
               * @dev Marks a hash as approved. This can be used to validate a hash that is used by a signature.
               * @param hashToApprove The hash that should be marked as approved for signatures that are verified by this contract.
               */
              function approveHash(bytes32 hashToApprove) external {
                  require(owners[msg.sender] != address(0), "GS030");
                  approvedHashes[msg.sender][hashToApprove] = 1;
                  emit ApproveHash(hashToApprove, msg.sender);
              }
              /// @dev Returns the chain id used by this contract.
              function getChainId() public view returns (uint256) {
                  uint256 id;
                  // solhint-disable-next-line no-inline-assembly
                  assembly {
                      id := chainid()
                  }
                  return id;
              }
              function domainSeparator() public view returns (bytes32) {
                  return keccak256(abi.encode(DOMAIN_SEPARATOR_TYPEHASH, getChainId(), this));
              }
              /// @dev Returns the bytes that are hashed to be signed by owners.
              /// @param to Destination address.
              /// @param value Ether value.
              /// @param data Data payload.
              /// @param operation Operation type.
              /// @param safeTxGas Gas that should be used for the safe transaction.
              /// @param baseGas Gas costs for that are independent of the transaction execution(e.g. base transaction fee, signature check, payment of the refund)
              /// @param gasPrice Maximum gas price that should be used for this transaction.
              /// @param gasToken Token address (or 0 if ETH) that is used for the payment.
              /// @param refundReceiver Address of receiver of gas payment (or 0 if tx.origin).
              /// @param _nonce Transaction nonce.
              /// @return Transaction hash bytes.
              function encodeTransactionData(
                  address to,
                  uint256 value,
                  bytes calldata data,
                  Enum.Operation operation,
                  uint256 safeTxGas,
                  uint256 baseGas,
                  uint256 gasPrice,
                  address gasToken,
                  address refundReceiver,
                  uint256 _nonce
              ) public view returns (bytes memory) {
                  bytes32 safeTxHash =
                      keccak256(
                          abi.encode(
                              SAFE_TX_TYPEHASH,
                              to,
                              value,
                              keccak256(data),
                              operation,
                              safeTxGas,
                              baseGas,
                              gasPrice,
                              gasToken,
                              refundReceiver,
                              _nonce
                          )
                      );
                  return abi.encodePacked(bytes1(0x19), bytes1(0x01), domainSeparator(), safeTxHash);
              }
              /// @dev Returns hash to be signed by owners.
              /// @param to Destination address.
              /// @param value Ether value.
              /// @param data Data payload.
              /// @param operation Operation type.
              /// @param safeTxGas Fas that should be used for the safe transaction.
              /// @param baseGas Gas costs for data used to trigger the safe transaction.
              /// @param gasPrice Maximum gas price that should be used for this transaction.
              /// @param gasToken Token address (or 0 if ETH) that is used for the payment.
              /// @param refundReceiver Address of receiver of gas payment (or 0 if tx.origin).
              /// @param _nonce Transaction nonce.
              /// @return Transaction hash.
              function getTransactionHash(
                  address to,
                  uint256 value,
                  bytes calldata data,
                  Enum.Operation operation,
                  uint256 safeTxGas,
                  uint256 baseGas,
                  uint256 gasPrice,
                  address gasToken,
                  address refundReceiver,
                  uint256 _nonce
              ) public view returns (bytes32) {
                  return keccak256(encodeTransactionData(to, value, data, operation, safeTxGas, baseGas, gasPrice, gasToken, refundReceiver, _nonce));
              }
          }
          // SPDX-License-Identifier: LGPL-3.0-only
          pragma solidity >=0.7.0 <0.9.0;
          import "../common/Enum.sol";
          /// @title Executor - A contract that can execute transactions
          /// @author Richard Meissner - <[email protected]>
          contract Executor {
              function execute(
                  address to,
                  uint256 value,
                  bytes memory data,
                  Enum.Operation operation,
                  uint256 txGas
              ) internal returns (bool success) {
                  if (operation == Enum.Operation.DelegateCall) {
                      // solhint-disable-next-line no-inline-assembly
                      assembly {
                          success := delegatecall(txGas, to, add(data, 0x20), mload(data), 0, 0)
                      }
                  } else {
                      // solhint-disable-next-line no-inline-assembly
                      assembly {
                          success := call(txGas, to, value, add(data, 0x20), mload(data), 0, 0)
                      }
                  }
              }
          }
          // SPDX-License-Identifier: LGPL-3.0-only
          pragma solidity >=0.7.0 <0.9.0;
          import "../common/SelfAuthorized.sol";
          /// @title Fallback Manager - A contract that manages fallback calls made to this contract
          /// @author Richard Meissner - <[email protected]>
          contract FallbackManager is SelfAuthorized {
              event ChangedFallbackHandler(address handler);
              // keccak256("fallback_manager.handler.address")
              bytes32 internal constant FALLBACK_HANDLER_STORAGE_SLOT = 0x6c9a6c4a39284e37ed1cf53d337577d14212a4870fb976a4366c693b939918d5;
              function internalSetFallbackHandler(address handler) internal {
                  bytes32 slot = FALLBACK_HANDLER_STORAGE_SLOT;
                  // solhint-disable-next-line no-inline-assembly
                  assembly {
                      sstore(slot, handler)
                  }
              }
              /// @dev Allows to add a contract to handle fallback calls.
              ///      Only fallback calls without value and with data will be forwarded.
              ///      This can only be done via a Safe transaction.
              /// @param handler contract to handle fallbacks calls.
              function setFallbackHandler(address handler) public authorized {
                  internalSetFallbackHandler(handler);
                  emit ChangedFallbackHandler(handler);
              }
              // solhint-disable-next-line payable-fallback,no-complex-fallback
              fallback() external {
                  bytes32 slot = FALLBACK_HANDLER_STORAGE_SLOT;
                  // solhint-disable-next-line no-inline-assembly
                  assembly {
                      let handler := sload(slot)
                      if iszero(handler) {
                          return(0, 0)
                      }
                      calldatacopy(0, 0, calldatasize())
                      // The msg.sender address is shifted to the left by 12 bytes to remove the padding
                      // Then the address without padding is stored right after the calldata
                      mstore(calldatasize(), shl(96, caller()))
                      // Add 20 bytes for the address appended add the end
                      let success := call(gas(), handler, 0, 0, add(calldatasize(), 20), 0, 0)
                      returndatacopy(0, 0, returndatasize())
                      if iszero(success) {
                          revert(0, returndatasize())
                      }
                      return(0, returndatasize())
                  }
              }
          }
          // SPDX-License-Identifier: LGPL-3.0-only
          pragma solidity >=0.7.0 <0.9.0;
          import "../common/Enum.sol";
          import "../common/SelfAuthorized.sol";
          interface Guard {
              function checkTransaction(
                  address to,
                  uint256 value,
                  bytes memory data,
                  Enum.Operation operation,
                  uint256 safeTxGas,
                  uint256 baseGas,
                  uint256 gasPrice,
                  address gasToken,
                  address payable refundReceiver,
                  bytes memory signatures,
                  address msgSender
              ) external;
              function checkAfterExecution(bytes32 txHash, bool success) external;
          }
          /// @title Fallback Manager - A contract that manages fallback calls made to this contract
          /// @author Richard Meissner - <[email protected]>
          contract GuardManager is SelfAuthorized {
              event ChangedGuard(address guard);
              // keccak256("guard_manager.guard.address")
              bytes32 internal constant GUARD_STORAGE_SLOT = 0x4a204f620c8c5ccdca3fd54d003badd85ba500436a431f0cbda4f558c93c34c8;
              /// @dev Set a guard that checks transactions before execution
              /// @param guard The address of the guard to be used or the 0 address to disable the guard
              function setGuard(address guard) external authorized {
                  bytes32 slot = GUARD_STORAGE_SLOT;
                  // solhint-disable-next-line no-inline-assembly
                  assembly {
                      sstore(slot, guard)
                  }
                  emit ChangedGuard(guard);
              }
              function getGuard() internal view returns (address guard) {
                  bytes32 slot = GUARD_STORAGE_SLOT;
                  // solhint-disable-next-line no-inline-assembly
                  assembly {
                      guard := sload(slot)
                  }
              }
          }
          // SPDX-License-Identifier: LGPL-3.0-only
          pragma solidity >=0.7.0 <0.9.0;
          import "../common/Enum.sol";
          import "../common/SelfAuthorized.sol";
          import "./Executor.sol";
          /// @title Module Manager - A contract that manages modules that can execute transactions via this contract
          /// @author Stefan George - <[email protected]>
          /// @author Richard Meissner - <[email protected]>
          contract ModuleManager is SelfAuthorized, Executor {
              event EnabledModule(address module);
              event DisabledModule(address module);
              event ExecutionFromModuleSuccess(address indexed module);
              event ExecutionFromModuleFailure(address indexed module);
              address internal constant SENTINEL_MODULES = address(0x1);
              mapping(address => address) internal modules;
              function setupModules(address to, bytes memory data) internal {
                  require(modules[SENTINEL_MODULES] == address(0), "GS100");
                  modules[SENTINEL_MODULES] = SENTINEL_MODULES;
                  if (to != address(0))
                      // Setup has to complete successfully or transaction fails.
                      require(execute(to, 0, data, Enum.Operation.DelegateCall, gasleft()), "GS000");
              }
              /// @dev Allows to add a module to the whitelist.
              ///      This can only be done via a Safe transaction.
              /// @notice Enables the module `module` for the Safe.
              /// @param module Module to be whitelisted.
              function enableModule(address module) public authorized {
                  // Module address cannot be null or sentinel.
                  require(module != address(0) && module != SENTINEL_MODULES, "GS101");
                  // Module cannot be added twice.
                  require(modules[module] == address(0), "GS102");
                  modules[module] = modules[SENTINEL_MODULES];
                  modules[SENTINEL_MODULES] = module;
                  emit EnabledModule(module);
              }
              /// @dev Allows to remove a module from the whitelist.
              ///      This can only be done via a Safe transaction.
              /// @notice Disables the module `module` for the Safe.
              /// @param prevModule Module that pointed to the module to be removed in the linked list
              /// @param module Module to be removed.
              function disableModule(address prevModule, address module) public authorized {
                  // Validate module address and check that it corresponds to module index.
                  require(module != address(0) && module != SENTINEL_MODULES, "GS101");
                  require(modules[prevModule] == module, "GS103");
                  modules[prevModule] = modules[module];
                  modules[module] = address(0);
                  emit DisabledModule(module);
              }
              /// @dev Allows a Module to execute a Safe transaction without any further confirmations.
              /// @param to Destination address of module transaction.
              /// @param value Ether value of module transaction.
              /// @param data Data payload of module transaction.
              /// @param operation Operation type of module transaction.
              function execTransactionFromModule(
                  address to,
                  uint256 value,
                  bytes memory data,
                  Enum.Operation operation
              ) public virtual returns (bool success) {
                  // Only whitelisted modules are allowed.
                  require(msg.sender != SENTINEL_MODULES && modules[msg.sender] != address(0), "GS104");
                  // Execute transaction without further confirmations.
                  success = execute(to, value, data, operation, gasleft());
                  if (success) emit ExecutionFromModuleSuccess(msg.sender);
                  else emit ExecutionFromModuleFailure(msg.sender);
              }
              /// @dev Allows a Module to execute a Safe transaction without any further confirmations and return data
              /// @param to Destination address of module transaction.
              /// @param value Ether value of module transaction.
              /// @param data Data payload of module transaction.
              /// @param operation Operation type of module transaction.
              function execTransactionFromModuleReturnData(
                  address to,
                  uint256 value,
                  bytes memory data,
                  Enum.Operation operation
              ) public returns (bool success, bytes memory returnData) {
                  success = execTransactionFromModule(to, value, data, operation);
                  // solhint-disable-next-line no-inline-assembly
                  assembly {
                      // Load free memory location
                      let ptr := mload(0x40)
                      // We allocate memory for the return data by setting the free memory location to
                      // current free memory location + data size + 32 bytes for data size value
                      mstore(0x40, add(ptr, add(returndatasize(), 0x20)))
                      // Store the size
                      mstore(ptr, returndatasize())
                      // Store the data
                      returndatacopy(add(ptr, 0x20), 0, returndatasize())
                      // Point the return data to the correct memory location
                      returnData := ptr
                  }
              }
              /// @dev Returns if an module is enabled
              /// @return True if the module is enabled
              function isModuleEnabled(address module) public view returns (bool) {
                  return SENTINEL_MODULES != module && modules[module] != address(0);
              }
              /// @dev Returns array of modules.
              /// @param start Start of the page.
              /// @param pageSize Maximum number of modules that should be returned.
              /// @return array Array of modules.
              /// @return next Start of the next page.
              function getModulesPaginated(address start, uint256 pageSize) external view returns (address[] memory array, address next) {
                  // Init array with max page size
                  array = new address[](pageSize);
                  // Populate return array
                  uint256 moduleCount = 0;
                  address currentModule = modules[start];
                  while (currentModule != address(0x0) && currentModule != SENTINEL_MODULES && moduleCount < pageSize) {
                      array[moduleCount] = currentModule;
                      currentModule = modules[currentModule];
                      moduleCount++;
                  }
                  next = currentModule;
                  // Set correct size of returned array
                  // solhint-disable-next-line no-inline-assembly
                  assembly {
                      mstore(array, moduleCount)
                  }
              }
          }
          // SPDX-License-Identifier: LGPL-3.0-only
          pragma solidity >=0.7.0 <0.9.0;
          import "../common/SelfAuthorized.sol";
          /// @title OwnerManager - Manages a set of owners and a threshold to perform actions.
          /// @author Stefan George - <[email protected]>
          /// @author Richard Meissner - <[email protected]>
          contract OwnerManager is SelfAuthorized {
              event AddedOwner(address owner);
              event RemovedOwner(address owner);
              event ChangedThreshold(uint256 threshold);
              address internal constant SENTINEL_OWNERS = address(0x1);
              mapping(address => address) internal owners;
              uint256 internal ownerCount;
              uint256 internal threshold;
              /// @dev Setup function sets initial storage of contract.
              /// @param _owners List of Safe owners.
              /// @param _threshold Number of required confirmations for a Safe transaction.
              function setupOwners(address[] memory _owners, uint256 _threshold) internal {
                  // Threshold can only be 0 at initialization.
                  // Check ensures that setup function can only be called once.
                  require(threshold == 0, "GS200");
                  // Validate that threshold is smaller than number of added owners.
                  require(_threshold <= _owners.length, "GS201");
                  // There has to be at least one Safe owner.
                  require(_threshold >= 1, "GS202");
                  // Initializing Safe owners.
                  address currentOwner = SENTINEL_OWNERS;
                  for (uint256 i = 0; i < _owners.length; i++) {
                      // Owner address cannot be null.
                      address owner = _owners[i];
                      require(owner != address(0) && owner != SENTINEL_OWNERS && owner != address(this) && currentOwner != owner, "GS203");
                      // No duplicate owners allowed.
                      require(owners[owner] == address(0), "GS204");
                      owners[currentOwner] = owner;
                      currentOwner = owner;
                  }
                  owners[currentOwner] = SENTINEL_OWNERS;
                  ownerCount = _owners.length;
                  threshold = _threshold;
              }
              /// @dev Allows to add a new owner to the Safe and update the threshold at the same time.
              ///      This can only be done via a Safe transaction.
              /// @notice Adds the owner `owner` to the Safe and updates the threshold to `_threshold`.
              /// @param owner New owner address.
              /// @param _threshold New threshold.
              function addOwnerWithThreshold(address owner, uint256 _threshold) public authorized {
                  // Owner address cannot be null, the sentinel or the Safe itself.
                  require(owner != address(0) && owner != SENTINEL_OWNERS && owner != address(this), "GS203");
                  // No duplicate owners allowed.
                  require(owners[owner] == address(0), "GS204");
                  owners[owner] = owners[SENTINEL_OWNERS];
                  owners[SENTINEL_OWNERS] = owner;
                  ownerCount++;
                  emit AddedOwner(owner);
                  // Change threshold if threshold was changed.
                  if (threshold != _threshold) changeThreshold(_threshold);
              }
              /// @dev Allows to remove an owner from the Safe and update the threshold at the same time.
              ///      This can only be done via a Safe transaction.
              /// @notice Removes the owner `owner` from the Safe and updates the threshold to `_threshold`.
              /// @param prevOwner Owner that pointed to the owner to be removed in the linked list
              /// @param owner Owner address to be removed.
              /// @param _threshold New threshold.
              function removeOwner(
                  address prevOwner,
                  address owner,
                  uint256 _threshold
              ) public authorized {
                  // Only allow to remove an owner, if threshold can still be reached.
                  require(ownerCount - 1 >= _threshold, "GS201");
                  // Validate owner address and check that it corresponds to owner index.
                  require(owner != address(0) && owner != SENTINEL_OWNERS, "GS203");
                  require(owners[prevOwner] == owner, "GS205");
                  owners[prevOwner] = owners[owner];
                  owners[owner] = address(0);
                  ownerCount--;
                  emit RemovedOwner(owner);
                  // Change threshold if threshold was changed.
                  if (threshold != _threshold) changeThreshold(_threshold);
              }
              /// @dev Allows to swap/replace an owner from the Safe with another address.
              ///      This can only be done via a Safe transaction.
              /// @notice Replaces the owner `oldOwner` in the Safe with `newOwner`.
              /// @param prevOwner Owner that pointed to the owner to be replaced in the linked list
              /// @param oldOwner Owner address to be replaced.
              /// @param newOwner New owner address.
              function swapOwner(
                  address prevOwner,
                  address oldOwner,
                  address newOwner
              ) public authorized {
                  // Owner address cannot be null, the sentinel or the Safe itself.
                  require(newOwner != address(0) && newOwner != SENTINEL_OWNERS && newOwner != address(this), "GS203");
                  // No duplicate owners allowed.
                  require(owners[newOwner] == address(0), "GS204");
                  // Validate oldOwner address and check that it corresponds to owner index.
                  require(oldOwner != address(0) && oldOwner != SENTINEL_OWNERS, "GS203");
                  require(owners[prevOwner] == oldOwner, "GS205");
                  owners[newOwner] = owners[oldOwner];
                  owners[prevOwner] = newOwner;
                  owners[oldOwner] = address(0);
                  emit RemovedOwner(oldOwner);
                  emit AddedOwner(newOwner);
              }
              /// @dev Allows to update the number of required confirmations by Safe owners.
              ///      This can only be done via a Safe transaction.
              /// @notice Changes the threshold of the Safe to `_threshold`.
              /// @param _threshold New threshold.
              function changeThreshold(uint256 _threshold) public authorized {
                  // Validate that threshold is smaller than number of owners.
                  require(_threshold <= ownerCount, "GS201");
                  // There has to be at least one Safe owner.
                  require(_threshold >= 1, "GS202");
                  threshold = _threshold;
                  emit ChangedThreshold(threshold);
              }
              function getThreshold() public view returns (uint256) {
                  return threshold;
              }
              function isOwner(address owner) public view returns (bool) {
                  return owner != SENTINEL_OWNERS && owners[owner] != address(0);
              }
              /// @dev Returns array of owners.
              /// @return Array of Safe owners.
              function getOwners() public view returns (address[] memory) {
                  address[] memory array = new address[](ownerCount);
                  // populate return array
                  uint256 index = 0;
                  address currentOwner = owners[SENTINEL_OWNERS];
                  while (currentOwner != SENTINEL_OWNERS) {
                      array[index] = currentOwner;
                      currentOwner = owners[currentOwner];
                      index++;
                  }
                  return array;
              }
          }
          // SPDX-License-Identifier: LGPL-3.0-only
          pragma solidity >=0.7.0 <0.9.0;
          /// @title Enum - Collection of enums
          /// @author Richard Meissner - <[email protected]>
          contract Enum {
              enum Operation {Call, DelegateCall}
          }
          // SPDX-License-Identifier: LGPL-3.0-only
          pragma solidity >=0.7.0 <0.9.0;
          /// @title EtherPaymentFallback - A contract that has a fallback to accept ether payments
          /// @author Richard Meissner - <[email protected]>
          contract EtherPaymentFallback {
              event SafeReceived(address indexed sender, uint256 value);
              /// @dev Fallback function accepts Ether transactions.
              receive() external payable {
                  emit SafeReceived(msg.sender, msg.value);
              }
          }
          // SPDX-License-Identifier: LGPL-3.0-only
          pragma solidity >=0.7.0 <0.9.0;
          /// @title SecuredTokenTransfer - Secure token transfer
          /// @author Richard Meissner - <[email protected]>
          contract SecuredTokenTransfer {
              /// @dev Transfers a token and returns if it was a success
              /// @param token Token that should be transferred
              /// @param receiver Receiver to whom the token should be transferred
              /// @param amount The amount of tokens that should be transferred
              function transferToken(
                  address token,
                  address receiver,
                  uint256 amount
              ) internal returns (bool transferred) {
                  // 0xa9059cbb - keccack("transfer(address,uint256)")
                  bytes memory data = abi.encodeWithSelector(0xa9059cbb, receiver, amount);
                  // solhint-disable-next-line no-inline-assembly
                  assembly {
                      // We write the return value to scratch space.
                      // See https://docs.soliditylang.org/en/v0.7.6/internals/layout_in_memory.html#layout-in-memory
                      let success := call(sub(gas(), 10000), token, 0, add(data, 0x20), mload(data), 0, 0x20)
                      switch returndatasize()
                          case 0 {
                              transferred := success
                          }
                          case 0x20 {
                              transferred := iszero(or(iszero(success), iszero(mload(0))))
                          }
                          default {
                              transferred := 0
                          }
                  }
              }
          }
          // SPDX-License-Identifier: LGPL-3.0-only
          pragma solidity >=0.7.0 <0.9.0;
          /// @title SelfAuthorized - authorizes current contract to perform actions
          /// @author Richard Meissner - <[email protected]>
          contract SelfAuthorized {
              function requireSelfCall() private view {
                  require(msg.sender == address(this), "GS031");
              }
              modifier authorized() {
                  // This is a function call as it minimized the bytecode size
                  requireSelfCall();
                  _;
              }
          }
          // SPDX-License-Identifier: LGPL-3.0-only
          pragma solidity >=0.7.0 <0.9.0;
          /// @title SignatureDecoder - Decodes signatures that a encoded as bytes
          /// @author Richard Meissner - <[email protected]>
          contract SignatureDecoder {
              /// @dev divides bytes signature into `uint8 v, bytes32 r, bytes32 s`.
              /// @notice Make sure to peform a bounds check for @param pos, to avoid out of bounds access on @param signatures
              /// @param pos which signature to read. A prior bounds check of this parameter should be performed, to avoid out of bounds access
              /// @param signatures concatenated rsv signatures
              function signatureSplit(bytes memory signatures, uint256 pos)
                  internal
                  pure
                  returns (
                      uint8 v,
                      bytes32 r,
                      bytes32 s
                  )
              {
                  // The signature format is a compact form of:
                  //   {bytes32 r}{bytes32 s}{uint8 v}
                  // Compact means, uint8 is not padded to 32 bytes.
                  // solhint-disable-next-line no-inline-assembly
                  assembly {
                      let signaturePos := mul(0x41, pos)
                      r := mload(add(signatures, add(signaturePos, 0x20)))
                      s := mload(add(signatures, add(signaturePos, 0x40)))
                      // Here we are loading the last 32 bytes, including 31 bytes
                      // of 's'. There is no 'mload8' to do this.
                      //
                      // 'byte' is not working due to the Solidity parser, so lets
                      // use the second best option, 'and'
                      v := and(mload(add(signatures, add(signaturePos, 0x41))), 0xff)
                  }
              }
          }
          // SPDX-License-Identifier: LGPL-3.0-only
          pragma solidity >=0.7.0 <0.9.0;
          /// @title Singleton - Base for singleton contracts (should always be first super contract)
          ///         This contract is tightly coupled to our proxy contract (see `proxies/GnosisSafeProxy.sol`)
          /// @author Richard Meissner - <[email protected]>
          contract Singleton {
              // singleton always needs to be first declared variable, to ensure that it is at the same location as in the Proxy contract.
              // It should also always be ensured that the address is stored alone (uses a full word)
              address private singleton;
          }
          // SPDX-License-Identifier: LGPL-3.0-only
          pragma solidity >=0.7.0 <0.9.0;
          /// @title StorageAccessible - generic base contract that allows callers to access all internal storage.
          /// @notice See https://github.com/gnosis/util-contracts/blob/bb5fe5fb5df6d8400998094fb1b32a178a47c3a1/contracts/StorageAccessible.sol
          contract StorageAccessible {
              /**
               * @dev Reads `length` bytes of storage in the currents contract
               * @param offset - the offset in the current contract's storage in words to start reading from
               * @param length - the number of words (32 bytes) of data to read
               * @return the bytes that were read.
               */
              function getStorageAt(uint256 offset, uint256 length) public view returns (bytes memory) {
                  bytes memory result = new bytes(length * 32);
                  for (uint256 index = 0; index < length; index++) {
                      // solhint-disable-next-line no-inline-assembly
                      assembly {
                          let word := sload(add(offset, index))
                          mstore(add(add(result, 0x20), mul(index, 0x20)), word)
                      }
                  }
                  return result;
              }
              /**
               * @dev Performs a delegetecall on a targetContract in the context of self.
               * Internally reverts execution to avoid side effects (making it static).
               *
               * This method reverts with data equal to `abi.encode(bool(success), bytes(response))`.
               * Specifically, the `returndata` after a call to this method will be:
               * `success:bool || response.length:uint256 || response:bytes`.
               *
               * @param targetContract Address of the contract containing the code to execute.
               * @param calldataPayload Calldata that should be sent to the target contract (encoded method name and arguments).
               */
              function simulateAndRevert(address targetContract, bytes memory calldataPayload) external {
                  // solhint-disable-next-line no-inline-assembly
                  assembly {
                      let success := delegatecall(gas(), targetContract, add(calldataPayload, 0x20), mload(calldataPayload), 0, 0)
                      mstore(0x00, success)
                      mstore(0x20, returndatasize())
                      returndatacopy(0x40, 0, returndatasize())
                      revert(0, add(returndatasize(), 0x40))
                  }
              }
          }
          // SPDX-License-Identifier: LGPL-3.0-only
          pragma solidity >=0.7.0 <0.9.0;
          /**
           * @title GnosisSafeMath
           * @dev Math operations with safety checks that revert on error
           * Renamed from SafeMath to GnosisSafeMath to avoid conflicts
           * TODO: remove once open zeppelin update to solc 0.5.0
           */
          library GnosisSafeMath {
              /**
               * @dev Multiplies two numbers, reverts on overflow.
               */
              function mul(uint256 a, uint256 b) internal pure returns (uint256) {
                  // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
                  // benefit is lost if 'b' is also tested.
                  // See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522
                  if (a == 0) {
                      return 0;
                  }
                  uint256 c = a * b;
                  require(c / a == b);
                  return c;
              }
              /**
               * @dev Subtracts two numbers, reverts on overflow (i.e. if subtrahend is greater than minuend).
               */
              function sub(uint256 a, uint256 b) internal pure returns (uint256) {
                  require(b <= a);
                  uint256 c = a - b;
                  return c;
              }
              /**
               * @dev Adds two numbers, reverts on overflow.
               */
              function add(uint256 a, uint256 b) internal pure returns (uint256) {
                  uint256 c = a + b;
                  require(c >= a);
                  return c;
              }
              /**
               * @dev Returns the largest of two numbers.
               */
              function max(uint256 a, uint256 b) internal pure returns (uint256) {
                  return a >= b ? a : b;
              }
          }
          // SPDX-License-Identifier: LGPL-3.0-only
          pragma solidity >=0.7.0 <0.9.0;
          contract ISignatureValidatorConstants {
              // bytes4(keccak256("isValidSignature(bytes,bytes)")
              bytes4 internal constant EIP1271_MAGIC_VALUE = 0x20c13b0b;
          }
          abstract contract ISignatureValidator is ISignatureValidatorConstants {
              /**
               * @dev Should return whether the signature provided is valid for the provided data
               * @param _data Arbitrary length data signed on the behalf of address(this)
               * @param _signature Signature byte array associated with _data
               *
               * MUST return the bytes4 magic value 0x20c13b0b when function passes.
               * MUST NOT modify state (using STATICCALL for solc < 0.5, view modifier for solc > 0.5)
               * MUST allow external calls
               */
              function isValidSignature(bytes memory _data, bytes memory _signature) public view virtual returns (bytes4);
          }
          

          File 8 of 8: ExecutionDelegate
          // SPDX-License-Identifier: MIT
          pragma solidity 0.8.17;
          import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
          import "@openzeppelin/contracts/token/ERC721/IERC721.sol";
          import "@openzeppelin/contracts/token/ERC1155/IERC1155.sol";
          import "@openzeppelin/contracts/access/Ownable.sol";
          import "@openzeppelin/contracts/utils/Address.sol";
          import {IExecutionDelegate} from "./interfaces/IExecutionDelegate.sol";
          /**
           * @title ExecutionDelegate
           * @dev Proxy contract to manage user token approvals
           */
          contract ExecutionDelegate is IExecutionDelegate, Ownable {
              using Address for address;
              mapping(address => bool) public contracts;
              mapping(address => bool) public revokedApproval;
              modifier approvedContract() {
                  require(contracts[msg.sender], "Contract is not approved to make transfers");
                  _;
              }
              event ApproveContract(address indexed _contract);
              event DenyContract(address indexed _contract);
              event RevokeApproval(address indexed user);
              event GrantApproval(address indexed user);
              /**
               * @dev Approve contract to call transfer functions
               * @param _contract address of contract to approve
               */
              function approveContract(address _contract) onlyOwner external {
                  contracts[_contract] = true;
                  emit ApproveContract(_contract);
              }
              /**
               * @dev Revoke approval of contract to call transfer functions
               * @param _contract address of contract to revoke approval
               */
              function denyContract(address _contract) onlyOwner external {
                  contracts[_contract] = false;
                  emit DenyContract(_contract);
              }
              /**
               * @dev Block contract from making transfers on-behalf of a specific user
               */
              function revokeApproval() external {
                  revokedApproval[msg.sender] = true;
                  emit RevokeApproval(msg.sender);
              }
              /**
               * @dev Allow contract to make transfers on-behalf of a specific user
               */
              function grantApproval() external {
                  revokedApproval[msg.sender] = false;
                  emit GrantApproval(msg.sender);
              }
              /**
               * @dev Transfer ERC721 token using `transferFrom`
               * @param collection address of the collection
               * @param from address of the sender
               * @param to address of the recipient
               * @param tokenId tokenId
               */
              function transferERC721Unsafe(address collection, address from, address to, uint256 tokenId)
                  approvedContract
                  external
              {
                  require(revokedApproval[from] == false, "User has revoked approval");
                  IERC721(collection).transferFrom(from, to, tokenId);
              }
              /**
               * @dev Transfer ERC721 token using `safeTransferFrom`
               * @param collection address of the collection
               * @param from address of the sender
               * @param to address of the recipient
               * @param tokenId tokenId
               */
              function transferERC721(address collection, address from, address to, uint256 tokenId)
                  approvedContract
                  external
              {
                  require(revokedApproval[from] == false, "User has revoked approval");
                  IERC721(collection).safeTransferFrom(from, to, tokenId);
              }
              /**
               * @dev Transfer ERC1155 token using `safeTransferFrom`
               * @param collection address of the collection
               * @param from address of the sender
               * @param to address of the recipient
               * @param tokenId tokenId
               * @param amount amount
               */
              function transferERC1155(address collection, address from, address to, uint256 tokenId, uint256 amount)
                  approvedContract
                  external
              {
                  require(revokedApproval[from] == false, "User has revoked approval");
                  IERC1155(collection).safeTransferFrom(from, to, tokenId, amount, "");
              }
              /**
               * @dev Transfer ERC20 token
               * @param token address of the token
               * @param from address of the sender
               * @param to address of the recipient
               * @param amount amount
               */
              function transferERC20(address token, address from, address to, uint256 amount)
                  approvedContract
                  external
              {
                  require(revokedApproval[from] == false, "User has revoked approval");
                  bytes memory data = abi.encodeWithSelector(IERC20.transferFrom.selector, from, to, amount);
                  bytes memory returndata = token.functionCall(data);
                  if (returndata.length > 0) {
                    require(abi.decode(returndata, (bool)), "ERC20 transfer failed");
                  }
              }
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts v4.4.1 (token/ERC20/IERC20.sol)
          pragma solidity ^0.8.0;
          /**
           * @dev Interface of the ERC20 standard as defined in the EIP.
           */
          interface IERC20 {
              /**
               * @dev Returns the amount of tokens in existence.
               */
              function totalSupply() external view returns (uint256);
              /**
               * @dev Returns the amount of tokens owned by `account`.
               */
              function balanceOf(address account) external view returns (uint256);
              /**
               * @dev Moves `amount` tokens from the caller's account to `recipient`.
               *
               * Returns a boolean value indicating whether the operation succeeded.
               *
               * Emits a {Transfer} event.
               */
              function transfer(address recipient, uint256 amount) external returns (bool);
              /**
               * @dev Returns the remaining number of tokens that `spender` will be
               * allowed to spend on behalf of `owner` through {transferFrom}. This is
               * zero by default.
               *
               * This value changes when {approve} or {transferFrom} are called.
               */
              function allowance(address owner, address spender) external view returns (uint256);
              /**
               * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
               *
               * Returns a boolean value indicating whether the operation succeeded.
               *
               * IMPORTANT: Beware that changing an allowance with this method brings the risk
               * that someone may use both the old and the new allowance by unfortunate
               * transaction ordering. One possible solution to mitigate this race
               * condition is to first reduce the spender's allowance to 0 and set the
               * desired value afterwards:
               * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
               *
               * Emits an {Approval} event.
               */
              function approve(address spender, uint256 amount) external returns (bool);
              /**
               * @dev Moves `amount` tokens from `sender` to `recipient` using the
               * allowance mechanism. `amount` is then deducted from the caller's
               * allowance.
               *
               * Returns a boolean value indicating whether the operation succeeded.
               *
               * Emits a {Transfer} event.
               */
              function transferFrom(
                  address sender,
                  address recipient,
                  uint256 amount
              ) external returns (bool);
              /**
               * @dev Emitted when `value` tokens are moved from one account (`from`) to
               * another (`to`).
               *
               * Note that `value` may be zero.
               */
              event Transfer(address indexed from, address indexed to, uint256 value);
              /**
               * @dev Emitted when the allowance of a `spender` for an `owner` is set by
               * a call to {approve}. `value` is the new allowance.
               */
              event Approval(address indexed owner, address indexed spender, uint256 value);
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721.sol)
          pragma solidity ^0.8.0;
          import "../../utils/introspection/IERC165.sol";
          /**
           * @dev Required interface of an ERC721 compliant contract.
           */
          interface IERC721 is IERC165 {
              /**
               * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
               */
              event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);
              /**
               * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
               */
              event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);
              /**
               * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
               */
              event ApprovalForAll(address indexed owner, address indexed operator, bool approved);
              /**
               * @dev Returns the number of tokens in ``owner``'s account.
               */
              function balanceOf(address owner) external view returns (uint256 balance);
              /**
               * @dev Returns the owner of the `tokenId` token.
               *
               * Requirements:
               *
               * - `tokenId` must exist.
               */
              function ownerOf(uint256 tokenId) external view returns (address owner);
              /**
               * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
               * are aware of the ERC721 protocol to prevent tokens from being forever locked.
               *
               * Requirements:
               *
               * - `from` cannot be the zero address.
               * - `to` cannot be the zero address.
               * - `tokenId` token must exist and be owned by `from`.
               * - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}.
               * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
               *
               * Emits a {Transfer} event.
               */
              function safeTransferFrom(
                  address from,
                  address to,
                  uint256 tokenId
              ) external;
              /**
               * @dev Transfers `tokenId` token from `from` to `to`.
               *
               * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
               *
               * Requirements:
               *
               * - `from` cannot be the zero address.
               * - `to` cannot be the zero address.
               * - `tokenId` token must be owned by `from`.
               * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
               *
               * Emits a {Transfer} event.
               */
              function transferFrom(
                  address from,
                  address to,
                  uint256 tokenId
              ) external;
              /**
               * @dev Gives permission to `to` to transfer `tokenId` token to another account.
               * The approval is cleared when the token is transferred.
               *
               * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
               *
               * Requirements:
               *
               * - The caller must own the token or be an approved operator.
               * - `tokenId` must exist.
               *
               * Emits an {Approval} event.
               */
              function approve(address to, uint256 tokenId) external;
              /**
               * @dev Returns the account approved for `tokenId` token.
               *
               * Requirements:
               *
               * - `tokenId` must exist.
               */
              function getApproved(uint256 tokenId) external view returns (address operator);
              /**
               * @dev Approve or remove `operator` as an operator for the caller.
               * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
               *
               * Requirements:
               *
               * - The `operator` cannot be the caller.
               *
               * Emits an {ApprovalForAll} event.
               */
              function setApprovalForAll(address operator, bool _approved) external;
              /**
               * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
               *
               * See {setApprovalForAll}
               */
              function isApprovedForAll(address owner, address operator) external view returns (bool);
              /**
               * @dev Safely transfers `tokenId` token from `from` to `to`.
               *
               * Requirements:
               *
               * - `from` cannot be the zero address.
               * - `to` cannot be the zero address.
               * - `tokenId` token must exist and be owned by `from`.
               * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
               * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
               *
               * Emits a {Transfer} event.
               */
              function safeTransferFrom(
                  address from,
                  address to,
                  uint256 tokenId,
                  bytes calldata data
              ) external;
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts v4.4.1 (token/ERC1155/IERC1155.sol)
          pragma solidity ^0.8.0;
          import "../../utils/introspection/IERC165.sol";
          /**
           * @dev Required interface of an ERC1155 compliant contract, as defined in the
           * https://eips.ethereum.org/EIPS/eip-1155[EIP].
           *
           * _Available since v3.1._
           */
          interface IERC1155 is IERC165 {
              /**
               * @dev Emitted when `value` tokens of token type `id` are transferred from `from` to `to` by `operator`.
               */
              event TransferSingle(address indexed operator, address indexed from, address indexed to, uint256 id, uint256 value);
              /**
               * @dev Equivalent to multiple {TransferSingle} events, where `operator`, `from` and `to` are the same for all
               * transfers.
               */
              event TransferBatch(
                  address indexed operator,
                  address indexed from,
                  address indexed to,
                  uint256[] ids,
                  uint256[] values
              );
              /**
               * @dev Emitted when `account` grants or revokes permission to `operator` to transfer their tokens, according to
               * `approved`.
               */
              event ApprovalForAll(address indexed account, address indexed operator, bool approved);
              /**
               * @dev Emitted when the URI for token type `id` changes to `value`, if it is a non-programmatic URI.
               *
               * If an {URI} event was emitted for `id`, the standard
               * https://eips.ethereum.org/EIPS/eip-1155#metadata-extensions[guarantees] that `value` will equal the value
               * returned by {IERC1155MetadataURI-uri}.
               */
              event URI(string value, uint256 indexed id);
              /**
               * @dev Returns the amount of tokens of token type `id` owned by `account`.
               *
               * Requirements:
               *
               * - `account` cannot be the zero address.
               */
              function balanceOf(address account, uint256 id) external view returns (uint256);
              /**
               * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {balanceOf}.
               *
               * Requirements:
               *
               * - `accounts` and `ids` must have the same length.
               */
              function balanceOfBatch(address[] calldata accounts, uint256[] calldata ids)
                  external
                  view
                  returns (uint256[] memory);
              /**
               * @dev Grants or revokes permission to `operator` to transfer the caller's tokens, according to `approved`,
               *
               * Emits an {ApprovalForAll} event.
               *
               * Requirements:
               *
               * - `operator` cannot be the caller.
               */
              function setApprovalForAll(address operator, bool approved) external;
              /**
               * @dev Returns true if `operator` is approved to transfer ``account``'s tokens.
               *
               * See {setApprovalForAll}.
               */
              function isApprovedForAll(address account, address operator) external view returns (bool);
              /**
               * @dev Transfers `amount` tokens of token type `id` from `from` to `to`.
               *
               * Emits a {TransferSingle} event.
               *
               * Requirements:
               *
               * - `to` cannot be the zero address.
               * - If the caller is not `from`, it must be have been approved to spend ``from``'s tokens via {setApprovalForAll}.
               * - `from` must have a balance of tokens of type `id` of at least `amount`.
               * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155Received} and return the
               * acceptance magic value.
               */
              function safeTransferFrom(
                  address from,
                  address to,
                  uint256 id,
                  uint256 amount,
                  bytes calldata data
              ) external;
              /**
               * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {safeTransferFrom}.
               *
               * Emits a {TransferBatch} event.
               *
               * Requirements:
               *
               * - `ids` and `amounts` must have the same length.
               * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155BatchReceived} and return the
               * acceptance magic value.
               */
              function safeBatchTransferFrom(
                  address from,
                  address to,
                  uint256[] calldata ids,
                  uint256[] calldata amounts,
                  bytes calldata data
              ) external;
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)
          pragma solidity ^0.8.0;
          import "../utils/Context.sol";
          /**
           * @dev Contract module which provides a basic access control mechanism, where
           * there is an account (an owner) that can be granted exclusive access to
           * specific functions.
           *
           * By default, the owner account will be the one that deploys the contract. This
           * can later be changed with {transferOwnership}.
           *
           * This module is used through inheritance. It will make available the modifier
           * `onlyOwner`, which can be applied to your functions to restrict their use to
           * the owner.
           */
          abstract contract Ownable is Context {
              address private _owner;
              event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
              /**
               * @dev Initializes the contract setting the deployer as the initial owner.
               */
              constructor() {
                  _transferOwnership(_msgSender());
              }
              /**
               * @dev Returns the address of the current owner.
               */
              function owner() public view virtual returns (address) {
                  return _owner;
              }
              /**
               * @dev Throws if called by any account other than the owner.
               */
              modifier onlyOwner() {
                  require(owner() == _msgSender(), "Ownable: caller is not the owner");
                  _;
              }
              /**
               * @dev Leaves the contract without owner. It will not be possible to call
               * `onlyOwner` functions anymore. Can only be called by the current owner.
               *
               * NOTE: Renouncing ownership will leave the contract without an owner,
               * thereby removing any functionality that is only available to the owner.
               */
              function renounceOwnership() public virtual onlyOwner {
                  _transferOwnership(address(0));
              }
              /**
               * @dev Transfers ownership of the contract to a new account (`newOwner`).
               * Can only be called by the current owner.
               */
              function transferOwnership(address newOwner) public virtual onlyOwner {
                  require(newOwner != address(0), "Ownable: new owner is the zero address");
                  _transferOwnership(newOwner);
              }
              /**
               * @dev Transfers ownership of the contract to a new account (`newOwner`).
               * Internal function without access restriction.
               */
              function _transferOwnership(address newOwner) internal virtual {
                  address oldOwner = _owner;
                  _owner = newOwner;
                  emit OwnershipTransferred(oldOwner, newOwner);
              }
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts v4.4.1 (utils/Address.sol)
          pragma solidity ^0.8.0;
          /**
           * @dev Collection of functions related to the address type
           */
          library Address {
              /**
               * @dev Returns true if `account` is a contract.
               *
               * [IMPORTANT]
               * ====
               * It is unsafe to assume that an address for which this function returns
               * false is an externally-owned account (EOA) and not a contract.
               *
               * Among others, `isContract` will return false for the following
               * types of addresses:
               *
               *  - an externally-owned account
               *  - a contract in construction
               *  - an address where a contract will be created
               *  - an address where a contract lived, but was destroyed
               * ====
               */
              function isContract(address account) internal view returns (bool) {
                  // This method relies on extcodesize, which returns 0 for contracts in
                  // construction, since the code is only stored at the end of the
                  // constructor execution.
                  uint256 size;
                  assembly {
                      size := extcodesize(account)
                  }
                  return size > 0;
              }
              /**
               * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
               * `recipient`, forwarding all available gas and reverting on errors.
               *
               * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
               * of certain opcodes, possibly making contracts go over the 2300 gas limit
               * imposed by `transfer`, making them unable to receive funds via
               * `transfer`. {sendValue} removes this limitation.
               *
               * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
               *
               * IMPORTANT: because control is transferred to `recipient`, care must be
               * taken to not create reentrancy vulnerabilities. Consider using
               * {ReentrancyGuard} or the
               * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
               */
              function sendValue(address payable recipient, uint256 amount) internal {
                  require(address(this).balance >= amount, "Address: insufficient balance");
                  (bool success, ) = recipient.call{value: amount}("");
                  require(success, "Address: unable to send value, recipient may have reverted");
              }
              /**
               * @dev Performs a Solidity function call using a low level `call`. A
               * plain `call` is an unsafe replacement for a function call: use this
               * function instead.
               *
               * If `target` reverts with a revert reason, it is bubbled up by this
               * function (like regular Solidity function calls).
               *
               * Returns the raw returned data. To convert to the expected return value,
               * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
               *
               * Requirements:
               *
               * - `target` must be a contract.
               * - calling `target` with `data` must not revert.
               *
               * _Available since v3.1._
               */
              function functionCall(address target, bytes memory data) internal returns (bytes memory) {
                  return functionCall(target, data, "Address: low-level call failed");
              }
              /**
               * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
               * `errorMessage` as a fallback revert reason when `target` reverts.
               *
               * _Available since v3.1._
               */
              function functionCall(
                  address target,
                  bytes memory data,
                  string memory errorMessage
              ) internal returns (bytes memory) {
                  return functionCallWithValue(target, data, 0, errorMessage);
              }
              /**
               * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
               * but also transferring `value` wei to `target`.
               *
               * Requirements:
               *
               * - the calling contract must have an ETH balance of at least `value`.
               * - the called Solidity function must be `payable`.
               *
               * _Available since v3.1._
               */
              function functionCallWithValue(
                  address target,
                  bytes memory data,
                  uint256 value
              ) internal returns (bytes memory) {
                  return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
              }
              /**
               * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
               * with `errorMessage` as a fallback revert reason when `target` reverts.
               *
               * _Available since v3.1._
               */
              function functionCallWithValue(
                  address target,
                  bytes memory data,
                  uint256 value,
                  string memory errorMessage
              ) internal returns (bytes memory) {
                  require(address(this).balance >= value, "Address: insufficient balance for call");
                  require(isContract(target), "Address: call to non-contract");
                  (bool success, bytes memory returndata) = target.call{value: value}(data);
                  return verifyCallResult(success, returndata, errorMessage);
              }
              /**
               * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
               * but performing a static call.
               *
               * _Available since v3.3._
               */
              function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
                  return functionStaticCall(target, data, "Address: low-level static call failed");
              }
              /**
               * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
               * but performing a static call.
               *
               * _Available since v3.3._
               */
              function functionStaticCall(
                  address target,
                  bytes memory data,
                  string memory errorMessage
              ) internal view returns (bytes memory) {
                  require(isContract(target), "Address: static call to non-contract");
                  (bool success, bytes memory returndata) = target.staticcall(data);
                  return verifyCallResult(success, returndata, errorMessage);
              }
              /**
               * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
               * but performing a delegate call.
               *
               * _Available since v3.4._
               */
              function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
                  return functionDelegateCall(target, data, "Address: low-level delegate call failed");
              }
              /**
               * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
               * but performing a delegate call.
               *
               * _Available since v3.4._
               */
              function functionDelegateCall(
                  address target,
                  bytes memory data,
                  string memory errorMessage
              ) internal returns (bytes memory) {
                  require(isContract(target), "Address: delegate call to non-contract");
                  (bool success, bytes memory returndata) = target.delegatecall(data);
                  return verifyCallResult(success, returndata, errorMessage);
              }
              /**
               * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
               * revert reason using the provided one.
               *
               * _Available since v4.3._
               */
              function verifyCallResult(
                  bool success,
                  bytes memory returndata,
                  string memory errorMessage
              ) internal pure returns (bytes memory) {
                  if (success) {
                      return returndata;
                  } else {
                      // Look for revert reason and bubble it up if present
                      if (returndata.length > 0) {
                          // The easiest way to bubble the revert reason is using memory via assembly
                          assembly {
                              let returndata_size := mload(returndata)
                              revert(add(32, returndata), returndata_size)
                          }
                      } else {
                          revert(errorMessage);
                      }
                  }
              }
          }
          // SPDX-License-Identifier: MIT
          pragma solidity 0.8.17;
          interface IExecutionDelegate {
              function approveContract(address _contract) external;
              function denyContract(address _contract) external;
              function revokeApproval() external;
              function grantApproval() external;
              function transferERC721Unsafe(address collection, address from, address to, uint256 tokenId) external;
              function transferERC721(address collection, address from, address to, uint256 tokenId) external;
              function transferERC1155(address collection, address from, address to, uint256 tokenId, uint256 amount) external;
              function transferERC20(address token, address from, address to, uint256 amount) external;
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)
          pragma solidity ^0.8.0;
          /**
           * @dev Interface of the ERC165 standard, as defined in the
           * https://eips.ethereum.org/EIPS/eip-165[EIP].
           *
           * Implementers can declare support of contract interfaces, which can then be
           * queried by others ({ERC165Checker}).
           *
           * For an implementation, see {ERC165}.
           */
          interface IERC165 {
              /**
               * @dev Returns true if this contract implements the interface defined by
               * `interfaceId`. See the corresponding
               * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
               * to learn more about how these ids are created.
               *
               * This function call must use less than 30 000 gas.
               */
              function supportsInterface(bytes4 interfaceId) external view returns (bool);
          }
          // SPDX-License-Identifier: MIT
          // OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
          pragma solidity ^0.8.0;
          /**
           * @dev Provides information about the current execution context, including the
           * sender of the transaction and its data. While these are generally available
           * via msg.sender and msg.data, they should not be accessed in such a direct
           * manner, since when dealing with meta-transactions the account sending and
           * paying for execution may not be the actual sender (as far as an application
           * is concerned).
           *
           * This contract is only required for intermediate, library-like contracts.
           */
          abstract contract Context {
              function _msgSender() internal view virtual returns (address) {
                  return msg.sender;
              }
              function _msgData() internal view virtual returns (bytes calldata) {
                  return msg.data;
              }
          }