TF_Graph* parent;
  TF_Output* parent_inputs;
};

struct TF_OperationDescription {
  TF_OperationDescription(TF_Graph* g, const char* op_type,
                          const char* node_name)
      : node_builder(node_name, op_type, g->graph.op_registry()), graph(g) {}

  tensorflow::NodeBuilder node_builder;
  TF_Graph* graph;
  std::set<std::string> colocation_constraints;
};

struct TF_Operation {

    TF_EXCLUSIVE_LOCKS_REQUIRED(desc->graph->mu) {
  Node* ret = nullptr;

  if (desc->graph->name_map.count(desc->node_builder.node_name())) {
    status->status = InvalidArgument("Duplicate node name in graph: '",
                                     desc->node_builder.node_name(), "'");
  } else {
    if (!desc->colocation_constraints.empty()) {
      desc->node_builder.Attr(
          tensorflow::kColocationAttrName,