code: def render_item(self, all_posts):
          
          index = all_posts.index(self)
          if index > 0:  # has newer posts
              newer_post = all_posts[index - 1]
          else:
              newer_post = None
  
          if index < len(all_posts) - 1:  # has older posts
              older_post = all_posts[index + 1]
          else:
              older_post = None
          return settings.JINJA_ENV.get_template(self.template).render(
              post=self,
              newer_post=newer_post,
              older_post=older_post,
              all_posts=all_posts,
              nav_context='post'
          )
docs: Renders the Post as HTML using the template specified in :attr:`html_template_path`.
  
          :param all_posts: An optional :class:`PostCollection` containing all of the posts in the site.
          :return: The rendered HTML as a string.