code: public MultiLayerNetwork fit(JavaRDD<DataSet> trainingData) {
          if (Nd4j.getExecutioner() instanceof GridExecutioner)
              ((GridExecutioner) Nd4j.getExecutioner()).flushQueue();
  
          trainingMaster.executeTraining(this, trainingData);
          network.incrementEpochCount();
          return network;
      }
docs: Fit the DataSet RDD
  
  @param trainingData the training data RDD to fitDataSet
  @return the MultiLayerNetwork after training