code: @Override
      public void validate() throws OpsGenieClientValidationException {
          super.validate();
          if (id == null)
              throw OpsGenieClientValidationException.missingMandatoryProperty(OpsGenieClientConstants.API.ID);
      }
docs: check the parameters for validation. It will be overridden by necessary
  Requests.
  
  @throws OpsGenieClientValidationException when id is null!