public function register($webinar_key, $registrantData)
 {
     $goToWebinar = new GoToWebinar($this->client);
     $response = $goToWebinar->register($webinar_key, $registrantData);
     if ($goToWebinar->hasErrors()) {
         $response = array('has_errors' => true, 'errors' => $goToWebinar->getErrors());
     } else {
         $response = array('has_errors' => false, 'joinUrl' => $goToWebinar->joinUrl);
     }
     return $response;
 }