code: def update_ret(self, space_no, field_types, key_tuple, op_list):
          
          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)
docs: send update command(s), updated tuple(s) is(are) sent back