code: def _send_flow(self, active):
          '''
          Send a flow control command.
          '''
          args = Writer()
          args.write_bit(active)
          self.send_frame(MethodFrame(self.channel_id, 20, 20, args))
          self.channel.add_synchronous_cb(self._recv_flow_okf _send_flow(self, active):
          '''
          Send a flow control command.
          '''
          args = Writer()
          args.write_bit(active)
          self.send_frame(MethodFrame(self.channel_id, 20, 20, args))
          self.channel.add_synchronous_cb(self._recv_flow_ok)
docs: Send a flow control command.