public static function stripTags($html, $allowable = [])
    {
        if (!is_array($allowable)) {
            $allowable = preg_split("/, */", $allowable, -1, PREG_SPLIT_NO_EMPTY);
        }

        if ($allowable) {
            return strip_tags($html, '<' . implode('><', $allowable) . '>');
        }

        return strip_tags($html);
    }