code: public Observable<ListModelsResult> listModelsAsync() {
          return listModelsWithServiceResponseAsync().map(new Func1<ServiceResponse<ListModelsResult>, ListModelsResult>() {
              @Override
              public ListModelsResult call(ServiceResponse<ListModelsResult> response) {
                  return response.body();
              }
          });
      }
docs: This operation returns the list of domain-specific models that are supported by the Computer Vision API.  Currently, the API only supports one domain-specific model: a celebrity recognizer. A successful response will be returned in JSON.  If the request failed, the response will contain an error code and a message to help understand what went wrong.
  
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the ListModelsResult object