public function get_response_code()
    {
        switch ($this->conn->resultcode) {
            case 'NOPERM':
                return self::NOPERM;
            case 'READ-ONLY':
                return self::READONLY;
            case 'TRYCREATE':
                return self::TRYCREATE;
            case 'INUSE':
                return self::INUSE;
            case 'OVERQUOTA':
                return self::OVERQUOTA;
            case 'ALREADYEXISTS':
                return self::ALREADYEXISTS;
            case 'NONEXISTENT':
                return self::NONEXISTENT;
            case 'CONTACTADMIN':
                return self::CONTACTADMIN;
            default:
                return self::UNKNOWN;
        }
    }