private function getPurifier($allowedTags)
    {
        $sanitizer = $this->getDefaultPurifier();

        $sanitizer->set('HTML.Allowed', $allowedTags);

        /**
         * Define custom HTML Definition for mark tool
         */
        if ($def = $sanitizer->maybeGetRawHTMLDefinition()) {
            $def->addElement('mark', 'Inline', 'Inline', 'Common');
        }

        $purifier = new \HTMLPurifier($sanitizer);

        return $purifier;
    }