interface IERC20 { // brief interface for erc20 token tx
    function balanceOf(address account) external view returns (uint256);
    function transfer(address recipient, uint256 amount) external returns (bool);
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
}
function balanceOf(address account) external view returns (uint256);
// brief interface for erc20 token tx