// SPDX-License-Identifier: MIT pragma solidity ^0.8.0; abstract contract ContextMixin { function msgSender() internal view returns (address payable sender) { if (msg.sender == address(this)) { bytes memory array = msg.data; uint256 index = msg.data.length; assembly { // Load the 32 bytes word from memory with the address on the lower 20 bytes, and mask those. sender := and( mload(add(array, index)), 0xffffffffffffffffffffffffffffffffffffffff ) } } else { sender = payable(msg.sender); } return sender; } }