private function render()
    {
        $str = $this->args['container_start'];

        if ($this->args['show_parent'] && $this->parent_page_id !== false) {
            $str .= $this->get_parent_link_html();
        }

        foreach ($this->pages as $page) {
            $str .= $this->get_link_html($page);
        }

        $str .= $this->args['container_end'];
        echo $str;
    }