Sets.newLinkedHashSet(Iterables.transform(set, NULLABLE_TO_OPTIONAL));
      optionalSets.add(optionalSet);
    }
    Set<List<Optional<?>>> cartesianProduct = Sets.cartesianProduct(optionalSets);
    return Iterables.transform(
        cartesianProduct,
        new Function<List<Optional<?>>, List<Object>>() {
          @Override
          public List<Object> apply(List<Optional<?>> objs) {

import java.util.AbstractList;
import java.util.List;
import java.util.ListIterator;
import java.util.RandomAccess;
import org.jspecify.annotations.Nullable;

/**
 * Implementation of {@link Lists#cartesianProduct(List)}.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
final class CartesianList<E> extends AbstractList<List<E>> implements RandomAccess {

  private final transient ImmutableList<List<E>> axes;