/**
  * @param       bool            $returnResponse     If true the CreateAccessTokenResponse will be returned
  * @return      CreateAccessTokenResponse
  * @throws      RequiredFieldMissingException|UnauthorizedClientException
  */
 public function requestAccessToken($returnResponse = false)
 {
     try {
         $accessTokenResponse = $this->api->requestAccessToken($returnResponse);
         if ($returnResponse) {
             return $accessTokenResponse;
         } else {
             return null;
         }
     } catch (RequestException $ex) {
         $caravanaException = CaravanaExceptionFactory::parseRequestException($ex);
         throw $caravanaException;
     }
 }