old_contents: #!/usr/bin/env python
  import pika
  import sys
  
  connection = pika.BlockingConnection(
      pika.ConnectionParameters(host='localhost'))
  channel = connection.channel()
  
  channel.queue_declare(queue='task_queue', durable=True)
  
  message = ' '.join(sys.argv[1:]) or "Hello World!"
  channel.basic_publish(
      exchange='',
      routing_key='task_queue',
      body=message,
      properties=pika.BasicProperties(
          delivery_mode=2,  # make message persistent
      ))
  print(" [x] Sent %r" % message)
  connection.close()
  
new_contents: #!/usr/bin/env python
  import pika
  import sys
  
  connection = pika.BlockingConnection(
      pika.ConnectionParameters(host='localhost'))
  channel = connection.channel()
  
  channel.queue_declare(queue='task_queue', durable=True)
  
  message = ' '.join(sys.argv[1:]) or "Hello World!"
  channel.basic_publish(
      exchange='',
      routing_key='task_queue',
      body=message,
      properties=pika.BasicProperties(
          delivery_mode=pika.spec.PERSISTENT_DELIVERY_MODE,
      ))
  print(" [x] Sent %r" % message)
  connection.close()
  
subject: Use named constant instead of 2 in `new_task.py`