public function addBulkAction($handlerClassName, $action = null)
    {
        if (!class_exists($handlerClassName)) {
            user_error("Bulk action handler not found: $handlerClassName", E_USER_ERROR);
        }

        $handler = Injector::inst()->get($handlerClassName);
        $urlSegment = $handler->config()->get('url_segment');
        if (!$urlSegment)
        {
            $rc = new ReflectionClass($handlerClassName);
            $urlSegment = $rc->getShortName();
        }

        $this->config['actions'][$urlSegment] = $handlerClassName;

        return $this;
    }