docs: @Override
      public void fit(@NonNull MultiDataSetIterator iterator) {
          Map<Integer, NormalizerStats.Builder> inputStatsBuilders = new HashMap<>();
          Map<Integer, NormalizerStats.Builder> outputStatsBuilders = new HashMap<>();
  
          iterator.reset();
          while (iterator.hasNext()) {
              fitPartial(iterator.next(), inputStatsBuilders, outputStatsBuilders);
          }
  
          inputStats = buildAllStats(inputStatsBuilders);
          outputStats = buildAllStats(outputStatsBuilders);
      }