public INDArray stack(int axis, INDArray... values) {
    Preconditions.checkArgument(values.length >= 1, "values has incorrect size/length. Expected: values.length >= 1, got %s", values.length);
    return Nd4j.exec(new org.nd4j.linalg.api.ops.impl.shape.Stack(values, axis))[0];
  }