code: def confirm_deliveries(self):
          
          self._confirming_deliveries = True
          confirm_frame = specification.Confirm.Select()
          return self.rpc_request(confirm_frame)
docs: Set the channel to confirm that each message has been
          successfully delivered.
  
          :raises AMQPChannelError: Raises if the channel encountered an error.
          :raises AMQPConnectionError: Raises if the connection
                                       encountered an error.
  
          :return: