public function addAssetLibrary($library_id, array $options = array())
    {
        $added = array();

        foreach ($this->library->getFiles($library_id) as $file) {

            $extension = pathinfo($file, PATHINFO_EXTENSION);

            if ($extension === 'js') {
                $result = $this->setJs($file, $options);
            } else if ($extension === 'css') {
                $result = $this->setCss($file, $options);
            }

            if (!empty($result)) {
                $added[] = $file;
            }
        }

        return $added;
    }