code: def url_norm (url, encoding=None):
      
      try:
          return urlutil.url_norm(url, encoding=encoding)
      except UnicodeError:
          msg = _("URL has unparsable domain name: %(name)s") % \
              {"name": sys.exc_info()[1]}
          raise LinkCheckerError(msg)
docs: Wrapper for url.url_norm() to convert UnicodeError in
      LinkCheckerError.