interface tokenRecipient {
    //function receiveApproval(address _from, uint256 _value, address _token, bytes calldata _extraData) external;
    function receiveApproval(address _from, uint256 _value, address _token, bytes _extraData) external;
}
function receiveApproval(address _from, uint256 _value, address _token, bytes _extraData) external;
//function receiveApproval(address _from, uint256 _value, address _token, bytes calldata _extraData) external;