public function getCustomResults($searchHandle, $isNewSearch, $previousSearchHandle = '')
 {
     // use previous search handle if not provided
     if (empty($previousSearchHandle) && $this->session->hasPreviousSearchHandle()) {
         $previousSearchHandle = $this->session->getPreviousSearchHandle();
     }
     $request = sprintf('GetCustomResults?Sitekey=%s&SearchHandle=%s&NewSearch=%s&PreviousSearchHandle=%s', $this->helper->getSiteKey(), $searchHandle, $isNewSearch ? '1' : '0', $previousSearchHandle);
     $response = $this->_request($request);
     // save previous search handle
     $previousSearchHandle = $response->QwiserSearchResults->getAttribute('SearchHandle');
     $this->session->setPreviousSearchHandle($previousSearchHandle);
     return $response;
 }