static public function getMarkdownRenderer()
    {
        if (!self::$markdownRendererInstance) {
            if (class_exists('\\Michelf\\Markdown')) {
                self::$markdownRendererInstance = new MichelfRenderer();
            } else {
                self::$markdownRendererInstance = new ParsedownRenderer();
            }
        }

        return self::$markdownRendererInstance;
    }