code: def add_menu_items_for_pages(self, pagequeryset=None, allow_subnav=True):
          
          item_manager = self.get_menu_items_manager()
          item_class = item_manager.model
          item_list = []
          i = item_manager.count()
          for p in pagequeryset.all():
              item_list.append(item_class(
                  menu=self, link_page=p, sort_order=i, allow_subnav=allow_subnav
              ))
              i += 1
          item_manager.bulk_create(item_list)
docs: Add menu items to this menu, linking to each page in `pagequeryset`
          (which should be a PageQuerySet instance)