code: def __check_response_for_fedex_error(self):
          
  
          if self.response.HighestSeverity == "FAILURE":
              for notification in self.response.Notifications:
                  if notification.Severity == "FAILURE":
                      raise FedexFailure(notification.Code,
                                         notification.Message)
docs: This checks the response for general Fedex errors that aren't related
          to any one WSDL.