code: @Override
      public void fit(DataSet dataSet) {
          featureStats = (S) newBuilder().addFeatures(dataSet).build();
          if (isFitLabel()) {
              labelStats = (S) newBuilder().addLabels(dataSet).build();
          }
      }
docs: Fit a dataset (only compute based on the statistics from this dataset)
  @param dataSet the dataset to compute on