protected function renderAttr($attributes = false, $params = false)
    {
        $attrStr = '';

        if (isset($attributes['callback'])) {
            $callbackParams = [$this];

            if ($params !== false) {
                array_push($callbackParams, $params);
            }

            call_user_func_array($attributes['callback'], $callbackParams);
        }

        if (is_array($attributes)) {
            foreach ($attributes as $attr => $value) {
                if (is_string($value)) {
                    $attrStr .= ' '.$attr.'="'.$value.'"';
                }
            }
        }

        return $attrStr;
    }