*/
    public ImmutableSet<@NonNull E> immutableCopy() {
      // Not using ImmutableSet.copyOf() to avoid iterating thrice (isEmpty, size, iterator).
      int maxSize = maxSize();
      if (maxSize == 0) {
        return ImmutableSet.of();
      }
      ImmutableSet.Builder<@NonNull E> builder = ImmutableSet.builderWithExpectedSize(maxSize);
      for (E element : this) {

        String[] values = null;
        if (input instanceof String[]) {
            values = (String[]) input;
        } else if (input instanceof List) {
            values = ((List<?>) input).stream().filter(Objects::nonNull).map(Object::toString).toArray(n -> new String[n]);
        } else if (input instanceof String) {
            return input.toString();
        }
        if (values != null) {

   * the spliterator implementation.
   */
  static final int SPLITERATOR_CHARACTERISTICS =
      Spliterator.IMMUTABLE | Spliterator.NONNULL | Spliterator.ORDERED;

  ImmutableCollection() {}

  /** Returns an unmodifiable iterator across the elements in this collection. */
  @Override
  public abstract UnmodifiableIterator<E> iterator();

      }
    };
  }

  @Override
  Spliterator<Cell<R, C, @Nullable V>> cellSpliterator() {
    return CollectSpliterators.<Cell<R, C, @Nullable V>>indexed(
        size(), Spliterator.ORDERED | Spliterator.NONNULL | Spliterator.DISTINCT, this::getCell);
  }

  private Cell<R, C, @Nullable V> getCell(int index) {
    return new Tables.AbstractCell<R, C, @Nullable V>() {
      final int rowIndex = index / columnList.size();

    Spliterator<Entry<K, V>> entrySpliterator() {
      return Spliterators.spliterator(
          entryIterator(),
          size(),
          Spliterator.DISTINCT | Spliterator.NONNULL | Spliterator.IMMUTABLE | Spliterator.ORDERED);
    }

    @Override
    ImmutableSet<K> createKeySet() {
      return new ImmutableMapKeySet<>(this);
    }

    @Override