code: public static Evaluation getEvaluation(ComputationGraph model, MultiDataSetIterator testData) {
          if (model.getNumOutputArrays() != 1)
              throw new IllegalStateException("GraphSetSetAccuracyScoreFunction cannot be "
                              + "applied to ComputationGraphs with more than one output. NumOutputs = "
                              + model.getNumOutputArrays());
  
          return model.evaluate(testData);
      }
docs: Get the evaluation
  for the given model and test dataset
  @param model the model to get the evaluation from
  @param testData the test data to do the evaluation on
  @return the evaluation object with accumulated statistics
  for the current test data