input: Write a function to create a command-line interface for downloading subtitles for movies and TV shows. The function should accept release paths as arguments and allow specifying the language and subtitle site to use. The available commands are "download", "exist", "test", "list", "help", and "version". The function should handle the provided commands and their respective options.
  def sub_cli():
      args = docopt(__doc__, help=True, version='Subtitles Client %s' % __version__)
  
      if args['download']:
          download_subtitles(args['<releases_path>'], args['--engine'], args['--lang'])
      elif args['exist']:
          is_subtitles_exist(args['<releases_path>'], args['--engine'], args['--lang'])
      elif args['test']:
          test_engines(args['<engines>'])
      elif args['--list']:
          for sub_site in SUBTITLE_SITE_LIST.keys():
              sub_dict = SUBTITLE_SITE_LIST.get(sub_site)
              print sub_dict.get('class_name')
  
  assert sub_cli()['<releases_path>']==['movie1', 'show1']
  assert sub_cli()['--lang']=='en'
  assert sub_cli()['--engine']==['site1']
  assert sub_cli()['--version']==True
  assert sub_cli()['--help']==True
output: def sub_cli():
      args = docopt(__doc__, help=True, version='Subtitles Client %s' % __version__)
  
      if args['download']:
          download_subtitles(args['<releases_path>'], args['--engine'], args['--lang'])
      elif args['exist']:
          is_subtitles_exist(args['<releases_path>'], args['--engine'], args['--lang'])
      elif args['test']:
          test_engines(args['<engines>'])
      elif args['--list']:
          for sub_site in SUBTITLE_SITE_LIST.keys():
              sub_dict = SUBTITLE_SITE_LIST.get(sub_site)
              print(sub_dict.get('class_name'))