// SPDX-License-Identifier: MIT pragma solidity 0.6.11; contract CheckContract { /** * Check that the account is an already deployed non-destroyed contract. * See: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/utils/Address.sol#L12 */ function checkContract(address _account) internal view { require(_account != address(0), "Account cannot be zero address"); uint256 size; // solhint-disable-next-line no-inline-assembly assembly { size := extcodesize(_account) } require(size > 0, "Account code size cannot be zero"); } }