title: How to verify my docker-compose.yml?
body: <p>I am setting up a container stack using docker-compose. Yet by running</p>
  
  <pre><code>docker-compose up
  </code></pre>
  
  <p>I get a rather cryptic error message:</p>
  
  <pre><code>Traceback (most recent call last):
    File "/usr/local/bin/docker-compose", line 9, in &lt;module&gt;
      load_entry_point('docker-compose==1.4.2', 'console_scripts', 'docker-compose')()
    File "/usr/local/lib/python2.7/dist-packages/compose/cli/main.py", line 39, in main
      command.sys_dispatch()
    File "/usr/local/lib/python2.7/dist-packages/compose/cli/docopt_command.py", line 21, in sys_dispatch
      self.dispatch(sys.argv[1:], None)
    File "/usr/local/lib/python2.7/dist-packages/compose/cli/command.py", line 27, in dispatch
      super(Command, self).dispatch(*args, **kwargs)
    File "/usr/local/lib/python2.7/dist-packages/compose/cli/docopt_command.py", line 24, in dispatch
      self.perform_command(*self.parse(argv, global_options))
    File "/usr/local/lib/python2.7/dist-packages/compose/cli/command.py", line 57, in perform_command
      verbose=options.get('--verbose'))
    File "/usr/local/lib/python2.7/dist-packages/compose/cli/command.py", line 78, in get_project
      config.load(config_details),
    File "/usr/local/lib/python2.7/dist-packages/compose/config.py", line 138, in load
      for service_name, service_dict in list(dictionary.items()):
  AttributeError: 'NoneType' object has no attribute 'items'
  </code></pre>
  
  <p>How to debug? I have checked that the yml is valid, yet it doesn't work.</p>