docs: public static boolean isBalanced(Set dataSet) {
          switch (dataSet) {
              case COMPLETE:
              case MERGE:
              case LETTERS:
                  //Note: EMNIST docs claims letters is balanced, but this is not possible for training set:
                  // 88800 examples / 26 classes = 3418.46
                  return false;
              case BALANCED:
              case DIGITS:
              case MNIST:
                  return true;
              default:
                  throw new UnsupportedOperationException("Unknown Set: " + dataSet);
          }
      }