public function canAdd()
    {
        $actor = $this->actor;
        $viewer = get_viewer();

        if ($actor) {
            if ($viewer->blocking($actor)) {
                return false;
            }

            $action = 'com_'.$this->_mixer->getIdentifier()->package.':'.$this->_mixer->getIdentifier()->name.':add';
            $ret = $actor->authorize('action', $action);

            return $ret !== false;
        }

        return false;
    }