docs: def do_flipper(parser, token):
      """The flipper tag takes two arguments: the user to look up and the feature
      to compare against.
      """
      nodelist = parser.parse(('endflipper',))
      tag_name, user_key, feature = token.split_contents()
      parser.delete_first_token()
      return FlipperNode(nodelist, user_key, feature)