* @param k The number of folds total.
* @param foldNum The current fold.
* @param fold The current fold.
*/
private void fitFold(int k, int foldNum, DataFold fold) {
MLMethod method = this.createMethod();
MLTrain train = this.createTrainer(method, fold.getTraining());
if (train.getImplementationType() == TrainingImplementationType.Iterative) {
SimpleEarlyStoppingStrategy earlyStop = new SimpleEarlyStoppingStrategy(
fold.getValidation());