code: @Override
      public void preProcess(@NonNull MultiDataSet toPreProcess) {
          int numFeatures = toPreProcess.numFeatureArrays();
          int numLabels = toPreProcess.numLabelsArrays();
  
          for (int i = 0; i < numFeatures; i++) {
              strategy.preProcess(toPreProcess.getFeatures(i), toPreProcess.getFeaturesMaskArray(i), getFeatureStats(i));
          }
          if (isFitLabel()) {
              for (int i = 0; i < numLabels; i++) {
                  strategy.preProcess(toPreProcess.getLabels(i), toPreProcess.getLabelsMaskArray(i), getLabelStats(i));
              }
          }
      }
docs: Pre process a MultiDataSet
  
  @param toPreProcess the data set to pre process