public static function dropdownToggleMenuLink($label, $url = '#', $htmlOptions = array(), $depth = 0)
    {
        self::addCssClass('dropdown-toggle', $htmlOptions);
        if ($depth === 0) {
            $label .= ' <b class="caret"></b>';
        }
        $htmlOptions['data-toggle'] = 'dropdown';
        return self::link($label, $url, $htmlOptions);
    }