code: public static UnitResponse createException(Throwable e, String errMsg) {
          return UnitResponse.createException(e).setMessage(errMsg);
      }
docs: Please pass an exception object to this method, and it returns a newly created response object with error code {@link Group#CODE_EXCEPTION}
  and the exception object as the data.
  
  @param e      the exception object.
  @param errMsg the error message that you want to add.