public static function getLibXmlLoaderOptions()
    {
        if (self::$libXmlLoaderOptions === null && defined('LIBXML_DTDLOAD')) {
            self::setLibXmlLoaderOptions(LIBXML_DTDLOAD | LIBXML_DTDATTR);
        } elseif (self::$libXmlLoaderOptions === null) {
            self::$libXmlLoaderOptions = true;
        }

        return self::$libXmlLoaderOptions;
    }