code: def iter_languages(self):
          
          default_lang = self.babel.default_locale.language
          default_title = self.babel.default_locale.get_display_name(
              default_lang)
  
          yield (default_lang, default_title)
  
          for l, title in current_app.config.get('I18N_LANGUAGES', []):
              yield l, title
docs: Iterate over list of languages.