code: def pages_siblings_menu(context, page, url='/'):
      
      lang = context.get('lang', pages_settings.PAGE_DEFAULT_LANGUAGE)
      page = get_page_from_string_or_id(page, lang)
      if page:
          if page.parent:
              root = page.parent
          else:
              root = page
          children = root.get_children_for_frontend()
          context.update({'children': children, 'page': page})
      return context
docs: Get the parent page of the given page and render a nested list of its
      child pages. Good for rendering a secondary menu.
  
      :param page: the page where to start the menu from.
      :param url: not used anymore.