input: 
  def download_subtitles(releases, engines=[DEFAULTS['subtitle_engine']], lang=DEFAULTS['subtitle_language']):
      """Downloads subtitles for the given releases using the specified subtitle engines and language.
      >>> download_subtitles(['path_to_movie1', 'path_to_movie2'], engines=['opensubtitles'], lang='en')
      """
  
output:     subtitles = []
      for release in releases:
          for engine in engines:
              subtitle = engine.search(release, lang)
              if subtitle:
                  subtitles.append(subtitle)
                  break
      return subtitles