code: def handle_ChannelCloseOK(self, frame):
          
          assert self.channel._closing, "received a not expected CloseOk"
          # Release the `close` method's future
          self.synchroniser.notify(spec.ChannelCloseOK)
  
          exc = ChannelClosed()
          self._close_all(exc)
docs: AMQP server closed channel as per our request