code: public Observable<ServiceResponse<Integer>> getUntaggedImageCountWithServiceResponseAsync(UUID projectId, UUID iterationId) {
          if (projectId == null) {
              throw new IllegalArgumentException("Parameter projectId is required and cannot be null.");
          }
          if (this.client.apiKey() == null) {
              throw new IllegalArgumentException("Parameter this.client.apiKey() is required and cannot be null.");
          }
          return service.getUntaggedImageCount(projectId, iterationId, this.client.apiKey(), this.client.acceptLanguage(), this.client.userAgent())
              .flatMap(new Func1<Response<ResponseBody>, Observable<ServiceResponse<Integer>>>() {
                  @Override
                  public Observable<ServiceResponse<Integer>> call(Response<ResponseBody> response) {
                      try {
                          ServiceResponse<Integer> clientResponse = getUntaggedImageCountDelegate(response);
                          return Observable.just(clientResponse);
                      } catch (Throwable t) {
                          return Observable.error(t);
                      }
                  }
              });
      }
docs: Gets the number of untagged images.
  This API returns the images which have no tags for a given project and optionally an iteration. If no iteration is specified the
  current workspace is used.
  
  @param projectId The project id
  @param iterationId The iteration id. Defaults to workspace
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the Integer object