public function themeUrl($url = null)
    {
        $themeDir = $this->getTheme()->getDirName();

        if (is_array($url)) {
            $_url = Url::to(CombineAssets::combine($url, themes_path().'/'.$themeDir));
        }
        else {
            $_url = Config::get('cms.themesPath', '/themes').'/'.$themeDir;
            if ($url !== null) {
                $_url .= '/'.$url;
            }
            $_url = Url::asset($_url);
        }

        return $_url;
    }