docs: def _format_as_url(path):
      """Make sure ``path`` takes the form of ``/some/url/``."""
      path = sub(r"\.html$", '', path)  # remove any ending .html
  
      # Make sure it starts/ends with a slash.
      if not path.startswith("/"):
          path = "/{0}".format(path)
      if not path.endswith("/"):
          path = "{0}/".format(path)
  
      return path