docs: public <K> JavaPairRDD<K, INDArray> feedForwardWithKeySingle(JavaPairRDD<K, INDArray> featuresData, int batchSize) {
          if (network.getNumInputArrays() != 1 || network.getNumOutputArrays() != 1) {
              throw new IllegalStateException(
                              "Cannot use this method with computation graphs with more than 1 input or output "
                                              + "( has: " + network.getNumInputArrays() + " inputs, "
                                              + network.getNumOutputArrays() + " outputs");
          }
          PairToArrayPair<K> p = new PairToArrayPair<>();
          JavaPairRDD<K, INDArray[]> rdd = featuresData.mapToPair(p);
          return feedForwardWithKey(rdd, batchSize).mapToPair(new ArrayPairToPair<K>());
      }