code: def extend_webfont_settings(webfont_settings):
      
      if not webfont_settings.get('fontdir_path', False):
          raise IcomoonSettingsError(("Webfont settings miss the required key "
                                      "item 'fontdir_path'"))
  
      if not webfont_settings.get('csspart_path', False):
          webfont_settings['csspart_path'] = None
  
      return webfont_settings
docs: Validate a webfont settings and optionally fill missing ``csspart_path``
      option.
  
      Args:
          webfont_settings (dict): Webfont settings (an item value from
              ``settings.ICOMOON_WEBFONTS``).
  
      Returns:
          dict: Webfont settings