@Override
  public boolean forEachEntry(@NotNull BiPredicate<? super K, ? super Set<VItem>> processor) throws IOException {
    return forEach((key, items) -> {
      try {
        ObjectOpenHashSet<VItem> values = new ObjectOpenHashSet<>();
        items.forEach(item -> {
          values.add(item);
        });
        return processor.test(key, values);
      }
      catch (IOException e) {
        throw new UncheckedIOException(e);
      }
    });
  }
@Override
  public boolean forEachEntry(@NotNull BiPredicate<? super K, ? super Set<VItem>> processor)