code: def tag_audio_file(audio_file, tracklisting):
      
      try:
          save_tag_to_audio_file(audio_file, tracklisting)
      # TODO: is IOError required now or would the mediafile exception cover it?
      except (IOError, mediafile.UnreadableFileError):
          print("Unable to save tag to file:", audio_file)
          audio_tagging_successful = False
      except TagNotNeededError:
          audio_tagging_successful = True
      else:
          audio_tagging_successful = True
      return audio_tagging_successful
docs: Adds tracklisting as list to lyrics tag of audio file if not present.
      Returns True if successful or not needed, False if tagging fails.