code: def list(declared, undeclared):
      
      queues = current_queues.queues.values()
      if declared:
          queues = filter(lambda queue: queue.exists, queues)
      elif undeclared:
          queues = filter(lambda queue: not queue.exists, queues)
      queue_names = [queue.routing_key for queue in queues]
      queue_names.sort()
      for queue in queue_names:
          click.secho(queue)
docs: List configured queues.