public function add($label, $url='')
    {
        if (is_array($label)) {
            if (count($label) > 0) foreach ($label as $crumb) {
                $defaults = [
                    'label' => '',
                    'url'   => ''
                ];
                $crumb = array_merge($defaults, $crumb);
                $this->add($crumb['label'], $crumb['url']);
            }
        } else {
            $label = trim(strip_tags($label, '<i><b><strong>'));
            if (! preg_match('|^http(s)?|', $url)) {
                $url = URL::to($url);
            }
            $this->crumbs[] = array('label' => $label, 'url' => $url);
        }

        return $this;
    }