public function shortcodeDate(Event $event, array $atts, $content, $tag)
    {
        if (!empty($atts['format']) && !empty($content)) {
            if (is_numeric($content)) {
                return date($atts['format'], $content);
            } else {
                return date($atts['format'], strtotime($content));
            }
        }

        return '';
    }