// as its an input requirement.
    if (!input_ty.hasRank() || input_ty.getRank() != 4) {
      return failure();
    }

    int64_t batch_cst = input_ty.getShape()[0];
    int64_t channels_cst = input_ty.getShape()[3];

    int64_t in_y_cst = input_ty.getShape()[1];
    int64_t in_x_cst = input_ty.getShape()[2];
    int64_t in_spatial_cst =

    private final ImmutableMap<E, Integer> inputSet;
    private final int mask;

    SubSet(ImmutableMap<E, Integer> inputSet, int mask) {
      this.inputSet = inputSet;
      this.mask = mask;
    }

    @Override
    public Iterator<E> iterator() {
      return new UnmodifiableIterator<E>() {
        final ImmutableList<E> elements = inputSet.keySet().asList();
        int remainingSetBits = mask;

    private final ImmutableMap<E, Integer> inputSet;
    private final int mask;

    SubSet(ImmutableMap<E, Integer> inputSet, int mask) {
      this.inputSet = inputSet;
      this.mask = mask;
    }

    @Override
    public Iterator<E> iterator() {
      return new UnmodifiableIterator<E>() {
        final ImmutableList<E> elements = inputSet.keySet().asList();
        int remainingSetBits = mask;