code: def get_post(id, check_author=True):
      
      post = Post.query.get_or_404(id, f"Post id {id} doesn't exist.")
  
      if check_author and post.author != g.user:
          abort(403)
  
      return post
docs: Get a post and its author by id.
  
      Checks that the id exists and optionally that the current user is
      the author.
  
      :param id: id of post to get
      :param check_author: require the current user to be the author
      :return: the post with author information
      :raise 404: if a post with the given id doesn't exist
      :raise 403: if the current user isn't the author