code: def _update_consumers(self):
          
          # Do we need to start more consumers.
          consumer_to_start = \
              min(max(self.number_of_consumers - len(self._consumers), 0), 2)
          for _ in range(consumer_to_start):
              consumer = Consumer(self.rpc_queue)
              self._start_consumer(consumer)
              self._consumers.append(consumer)
  
          # Check that all our consumers are active.
          for consumer in self._consumers:
              if consumer.active:
                  continue
              self._start_consumer(consumer)
              break
  
          # Do we have any overflow of consumers.
          self._stop_consumers(self.number_of_consumers)
docs: Update Consumers.
  
              - Add more if requested.
              - Make sure the consumers are healthy.
              - Remove excess consumers.
  
          :return: