args_.push_back(arg);
  }
  Node* dst_node = edge->dst();
  Node* dst_image = node_images.at(dst_node);
  int dst_slot = edge->dst_input();
  args_by_dst_[InputTensor(dst_node, dst_slot)] = arg_index;
  graph_->AddEdge(args_[arg_index], 0, dst_image, dst_slot);
  return absl::OkStatus();
}

Status Encapsulator::Subgraph::RecordControlResult(
    const Edge* edge,
    const absl::flat_hash_map<const Node*, Node*>& node_images) {

  // Create the backedges from the NextIteration nodes to the Merge nodes.
  for (size_t i = 0; i < num_loop_vars; ++i) {
    const int merge_backedge_output_index = 1;
    scope.graph()->AddEdge(next_outputs[i].node(), next_outputs[i].index(),
                           merge_outputs[i].node(),
                           merge_backedge_output_index);
  }

  outputs->resize(num_loop_vars);

      for (E edge : network.outEdges(node)) {
        N successorNode = network.incidentNodes(edge).adjacentNode(node);
        if (subgraph.nodes().contains(successorNode)) {
          subgraph.addEdge(node, successorNode, edge);
        }
      }
    }
    return subgraph;
  }

  /** Creates a mutable copy of {@code graph} with the same nodes and edges. */

  auto var =
      ops::VarHandleOp(root.WithOpName("var"), DT_INT32, TensorShape({}));
  auto int32_on_device =
      ops::ReadVariableOp(root.WithOpName("int32_on_device"), var, DT_INT32);

  root.graph()->AddEdge(int32_on_device.node(), 0, call, 0);

  std::unique_ptr<Graph> graph;
  TF_ASSERT_OK(BuildXlaOps(root, fdef_lib, &graph));

  Node* stateful_partitioned_call_op = nullptr;
  for (Node* n : graph->op_nodes()) {

      for (E edge : network.outEdges(node)) {
        N successorNode = network.incidentNodes(edge).adjacentNode(node);
        if (subgraph.nodes().contains(successorNode)) {
          subgraph.addEdge(node, successorNode, edge);
        }
      }
    }
    return subgraph;
  }

  /** Creates a mutable copy of {@code graph} with the same nodes and edges. */

              graph->RemoveEdge(e);
            } else {
              Node* dst = e->dst();
              int dst_input = e->dst_input();
              graph->RemoveEdge(e);
              graph->AddEdge(const_node, 0, dst, dst_input);
            }
          }
        }
      }
    }

    // Merge node causes a loop so we remove NextIteration->Merge edge before

	if err != nil {
		log.Fatal(err)
	}

	var out []byte
	if *flagDot {
		var b bytes.Buffer
		g.TransitiveReduction()
		// Add cyclic edges for visualization.
		for k := range cyclicRanks {
			g.AddEdge(k, k)
		}
		// Reverse the graph. It's much easier to read this as
		// a "<" partial order than a ">" partial order. This
		// ways, locks are acquired from the top going down

    DCHECK(e->src_output() == 0 || e->src_output() == Graph::kControlSlot);

    int src_output = e->src_output();
    int dst_input = e->dst_input();
    Node* dst = e->dst();
    g->RemoveEdge(e);
    g->AddEdge(static_shaped_slice, src_output, dst, dst_input);
  }

  for (const Edge* e : slice->in_edges()) {
    if (e->IsControlEdge()) {
      g->AddControlEdge(e->src(), static_shaped_slice);
    }
  }

    TF_CHECK_OK(NodeDefBuilder("fn", "fn", &fld)
                    .Input("const", 0, DT_INT32)
                    .Finalize(&fn_def));
    Node *fn_node = g->AddNode(fn_def, &s);
    TF_CHECK_OK(s);
    g->AddEdge(const_node, 0, fn_node, 0);

    NodeDef ret_def;
    TF_CHECK_OK(NodeDefBuilder("ret", "_Retval")
                    .Attr("index", 0)
                    .Attr("T", DT_INT32)

    MutableNetwork<String, Integer> network = NetworkBuilder.directed().build();
    network.addEdge("a", "b", 11);

    Traverser.forTree(network); // Does not throw
  }

  @Test
  public void forTree_withUndirectedNetwork_throws() throws Exception {
    MutableNetwork<String, Integer> network = NetworkBuilder.undirected().build();
    network.addEdge("a", "b", 11);