@Override
      public @NotNull Iterator<Chunk<Node>> getIn(Chunk<Node> chunk) {
        final Set<Node> chunkNodes = chunk.getNodes();
        final Set<Chunk<Node>> ins = new LinkedHashSet<>();
        for (final Node node : chunkNodes) {
          for (Iterator<Node> nodeIns = graph.getIn(node); nodeIns.hasNext(); ) {
            final Node in = nodeIns.next();
            if (!chunk.containsNode(in)) {
              ins.add(nodeToChunkMap.get(in));
            }
          }
        }
        return ins.iterator();
      }
@Override
      public @NotNull Iterator<Chunk<Node>> getIn(Chunk<Node> chunk)