input: def subtitles_cli(command: str, releases: List[str], engines: List[str] = None, lang: str = None) -> None:
      """ This function provides a command-line interface to download subtitles for movies and TV shows. 
      The available commands are "download", "exist", "test", "list", "help", and "version".
      Provide one or more release paths as arguments and optionally specify the language and subtitle site to use.
  
      >>> subtitles_cli("download", ["path/to/movie1", "path/to/movie2"], ["engine1"], "en")
      """
output:     if command == "download":
          for release in releases:
              print(f"Downloading subtitles for {release} using {engines[0]} engine in {lang} language.")
      elif command == "exist":
          for release in releases:
              print(f"Checking if subtitles exist for {release} using {engines[0]} engine in {lang} language.")
      elif command == "test":
          for release in releases:
              print(f"Testing subtitles for {release} using {engines[0]} engine in {lang} language.")
      elif command == "list":
          print("Listing available subtitles:")
          for release in releases:
              print(f"- {release} using {engines[0]} engine in {lang} language.")
      elif command == "help":
          print("Available commands: download, exist, test, list, help, version")
          print("Usage: subtitles_cli(command, releases, engines=None, lang=None)")
      elif command == "version":
          print("Subtitles CLI version 1.0")
      else:
          print(f"Unknown command: {command}. Use 'help' for available commands.")