public static function getLiteralType ($literal)
    {
        preg_match('/^".*"(?:\^\^([^"]+)|(@)[^@"]+)?$/s',$literal,$match);//TODO: somehow the copied regex did not work. To be checked. Contained [^] instead of the .
        if (empty($match))
            throw new \Exception($literal . ' is not a literal');
        if (!empty($match[1])) {
            return $match[1];
        } else {
            return !empty($match[2]) ? self::RDFLANGSTRING : self::XSDSTRING;
        }
    }