old_contents: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  servers = [
      {'name': 'server1', 'host': '127.0.0.1', 'port': 6379, 'db': 0},
      {'name': 'server2', 'host': '127.0.0.1', 'port': 6379, 'db': 0},
      {'name': 'server3', 'host': '127.0.0.1', 'port': 6379, 'db': 0},
      {'name': 'server4', 'host': '127.0.0.1', 'port': 6379, 'db': 0},
  ]
  
new_contents: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  servers = [
      {'name': 'server1', 'host': '127.0.0.1', 'port': 6376, 'db': 0},
      {'name': 'server2', 'host': '127.0.0.1', 'port': 6377, 'db': 0},
      {'name': 'server3', 'host': '127.0.0.1', 'port': 6378, 'db': 0},
      {'name': 'server4', 'host': '127.0.0.1', 'port': 6379, 'db': 0},
  ]
  
subject: make example more distinct