def METHOD_NAME(self, queue_name):
    """Declare a queue.  Has no effect if a queue with the given
    name has already been declared.
    Parameters:
      queue_name(str): The name of the new queue.
    """
    if queue_name not in self.queues:
        self.emit_before("declare_queue", queue_name)
        self.queues[queue_name] = Queue()
        self.emit_after("declare_queue", queue_name)
        delayed_name = dq_name(queue_name)
        self.queues[delayed_name] = Queue()
        self.delay_queues.add(delayed_name)
        self.emit_after("declare_delay_queue", delayed_name)