code: function urlFormat(obj) {
    // ensure it's an object, and not a string url.
    // If it's an obj, this is a no-op.
    // this way, you can call url_format() on strings
    // to clean up potentially wonky urls.
    if (util.isString(obj)) { obj = urlParse(obj); }
    if (!(obj instanceof Url)) { return Url.prototype.format.call(obj); }
    return obj.format();
  }
docs: format a parsed object into a url string