code: def get_broker() -> "Broker":
      
      global global_broker
      if global_broker is None:
          from .brokers.rabbitmq import RabbitmqBroker
  
          set_broker(RabbitmqBroker(
              host="127.0.0.1",
              port=5672,
              heartbeat=5,
              connection_attempts=5,
              blocked_connection_timeout=30,
          ))
      return global_broker
docs: Get the global broker instance.  If no global broker is set,
      this initializes a RabbitmqBroker and returns it.
  
      Returns:
        Broker: The default Broker.