docs: def get_template_i18n(template_name, locale):
      """Build template list with preceding locale if found."""
      if locale is None:
          return [template_name]
  
      template_list = []
      parts = template_name.rsplit(".", 1)
      root = parts[0]
      suffix = parts[1]
  
      if locale.territory is not None:
          locale_string = "_".join([locale.language, locale.territory])
          localized_template_path = ".".join([root, locale_string, suffix])
          template_list.append(localized_template_path)
  
      localized_template_path = ".".join([root, locale.language, suffix])
      template_list.append(localized_template_path)
  
      # append the default
      template_list.append(template_name)
      return template_list