def update_ret(self, space_no, field_types, key_tuple, op_list):
        """
        send update command(s), updated tuple(s) is(are) sent back
        """
        d = self.replyQueue.get()
        packet = RequestUpdate(self.charset, self.errors, d._ipro_request_id,
                               space_no, Request.TNT_FLAG_RETURN, key_tuple, op_list)
        self.transport.write(bytes(packet))
        return d.addCallback(self.handle_reply, self.charset, self.errors, field_types)