src/Pair.sol:

 function withdraw(uint256 tokenId) public {
        // check that the sender is the caviar owner
        require(caviar.owner() == msg.sender, "Withdraw: not owner");

        // check that the close period has been set
        require(closeTimestamp != 0, "Withdraw not initiated");

        // check that the close grace period has passed
        require(block.timestamp >= closeTimestamp, "Not withdrawable yet");

        // transfer the nft to the caviar owner
        ERC721(nft).safeTransferFrom(address(this), msg.sender, tokenId);

        emit Withdraw(tokenId);
    }
reentrancy.sol:
 function onERC721Received(
    address,
    address,
    uint256,
    bytes memory
  ) public virtual override returns (bytes4) {
    //...do something
    }
    return this.onERC721Received.selector;
  }
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.13;

contract ReEntrancyGuard {
    bool internal locked;

    modifier noReentrant() {
        require(!locked, "No re-entrancy");
        locked = true;
        _;
        locked = false;
    }
}
