// SPDX-License-Identifier: MIT pragma solidity >=0.6.12; contract Utils { /** constructor */ constructor() public { } // verifies that an amount is greater than zero modifier greaterThanZero(uint256 _amount) { require(_amount > 0); _; } // validates an address - currently only checks that it isn't null modifier validAddress(address _address) { require(_address != address(0)); _; } // verifies that the address is different than this contract address modifier notThis(address _address) { require(_address != address(this)); _; } }