public static function isBool(&$var = null): bool
    {
        // will return true for "1", true, "on", "yes", false for 0, "false", "off", 'no', '', NULL FOR ANY OTHER VALUE!!!
        $parse = filter_var($var, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE);
        if ($parse !== null) {
            $var = $parse;
            return true;
        }
        return false;
    }