def url_norm (url, encoding=None):
    """Wrapper for url.url_norm() to convert UnicodeError in
    LinkCheckerError."""
    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)
Wrapper for url.url_norm() to convert UnicodeError in
    LinkCheckerError.