code: def _do_close(self):
          
          AMQP_LOGGER.debug('Closed channel #%d', self.channel_id)
          self.is_open = False
          channel_id, self.channel_id = self.channel_id, None
          connection, self.connection = self.connection, None
          if connection:
              connection.channels.pop(channel_id, None)
              connection._avail_channel_ids.append(channel_id)
          self.callbacks.clear()
          self.cancel_callbacks.clear()
          self.events.clear()
          self.no_ack_consumers.clear()
docs: Tear down this object, after we've agreed to close
          with the server.