protected function createNavbarMenuClass(AbstractPage $page, $ulClass, $depth)
    {
        if ($depth === 0 && $ulClass) {
            return ' class="' . $this->escapeHtmlAttribute($ulClass) . '"';
        } elseif ($page->getParent() && $depth <= self::MAX_RENDER_DEPTH) {
            return ' class="dropdown-menu"';
        }

        return '';
    }