final protected function checkBooleanResponse(string $res):int
    {
        if (trim($res) == "yes" || trim($res) == "no" || trim($res) == "") {
            return (1);
        }
        return (-1);
    }
final protected function checkBooleanResponse(string $res):int
    {
        if (trim($res) == "yes" || trim($res) == "no" || trim($res) == "") {
            return (1);
        }
        return (-1);
    }
final protected function checkBooleanResponse ( string $ res ) : int { if ( trim ( $ res ) == "yes" || trim ( $ res ) == "no" || trim ( $ res ) == "" ) { return ( 1 ) ; } return ( - 1 ) ; }
Check boolean response
@param string $res response
@return int Is valid boolean response
Check boolean response