protected function sanitizeString($string)
    {
        // clean content
        $string = HtmlContentExtractor::cleanContent($string);
        $string = html_entity_decode($string, ENT_QUOTES, 'UTF-8');
        $string = filter_var(strip_tags($string), FILTER_SANITIZE_STRING); // after entity decoding we might have tags again
        $string = trim($string);

        return $string;
    }