public static function filter($html, array $config = null, $spec = null) {
        require_once __DIR__.'/htmLawed/htmLawed.php';

        if ($config === null) {
            $config = self::$defaultConfig;
        }

        if (isset($config['spec']) && !$spec) {
            $spec = $config['spec'];
        }

        if ($spec === null) {
            $spec = static::$defaultSpec;
        }

        return htmLawed($html, $config, $spec);
    }