protected function applyRequestParameters(Request $request, $listBuilder)
    {
        if (json_decode($request->get('hasNoParent', null))) {
            $listBuilder->where($this->getFieldDescriptorForNoParent(), null);
        }

        if (json_decode($request->get('hasEmail', null))) {
            $listBuilder->whereNot($this->getFieldDescriptors()['mainEmail'], null);
        }
    }