如何将芹菜任务订阅到现有的RabbitMQ exchange？

import pika

# 创建一个连接到RabbitMQ服务器的通道
connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))
channel = connection.channel()

# 声明一个消费者，指定要订阅的exchange和queue
channel.exchange_declare(exchange='my_exchange', exchange_type='direct')
channel.queue_declare(queue='my_queue')
channel.queue_bind(exchange='my_exchange', queue='my_queue', routing_key='my_routing_key')

# 编写一个回调函数，用于处理接收到的消息
def callback(ch, method, properties, body):
    print("Received message:", body)

# 将回调函数绑定到消费者上
channel.basic_consume(queue='my_queue', on_message_callback=callback, auto_ack=True)

# 启动消费者，开始接收和处理消息
channel.start_consuming()