code: public NaluErrorMessage getErrorMessageByPriority() {
      if (!Objects.isNull(this.naluErrorMessage)) {
        return this.naluErrorMessage;
      } else if (!Objects.isNull(this.applicationErrorMessage)) {
        return this.applicationErrorMessage;
      } else {
        return null;
      }
    }
docs: Returns the last error message set by Nalu or application.
  <p>
  In case a error message is set by Nalu and by the application,
  this method will return the error message set by Nalu.
  <p>
  Once the error message is consumed, it should be reseted by the developer.
  (after displayed on the error site!)
  
  @return the last set error message set by thel application
  or null, if there is none