code: @Override
      public DataSet filterBy(int[] labels) {
          List<DataSet> list = asList();
          List<DataSet> newList = new ArrayList<>();
          List<Integer> labelList = new ArrayList<>();
          for (int i : labels)
              labelList.add(i);
          for (DataSet d : list) {
              int outcome = d.outcome();
              if (labelList.contains(outcome)) {
                  newList.add(d);
              }
          }
  
          return DataSet.merge(newList);
      }
docs: Strips the data transform of all but the passed in labels
  
  @param labels strips the data transform of all but the passed in labels
  @return the dataset with only the specified labels