code: protected function request($access, $request, $endpointurl)
      {
          $requestInstance = new Request($this->logger);
          $response = $requestInstance->request($access, $request, $endpointurl);
          if ($response->getResponse() instanceof SimpleXMLElement) {
              $this->response = $response->getResponse();
  
              return $response->getResponse();
          }
  
          throw new Exception('Failure: Response is invalid.');
      }
docs: Send request to UPS.
  
  @param string $access The access request xml
  @param string $request The request xml
  @param string $endpointurl The UPS API Endpoint URL
  
  @throws Exception
  
  @return SimpleXMLElement
  
  @deprecated Untestable