code: def _check_response_for_request_errors(self):
          
          if self.response.HighestSeverity == "ERROR":  # pragma: no cover
              for notification in self.response.Notifications:
                  if notification.Severity == "ERROR":
                      if "Invalid tracking number" in notification.Message:
                          raise FedexInvalidTrackingNumber(
                                  notification.Code, notification.Message)
                      else:
                          raise FedexError(notification.Code, notification.Message)
docs: Checks the response to see if there were any errors specific to
          this WSDL.