};

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 {
  tensorflow::Node node;

 private:

}

// TF_Graph functions ---------------------------------------------------------

TF_Graph::TF_Graph()
    : graph(tensorflow::OpRegistry::Global()),
      refiner(graph.versions().producer(), graph.op_registry()),
      delete_requested(false),
      parent(nullptr),
      parent_inputs(nullptr) {
  // Tell the shape refiner to also run shape inference on functions.

    return nullptr;
  }

  // The returned string is owned by OpRegistry, so liveness is not a concern.
  return input_arg.number_attr().c_str();
}

int TF_OpIsStateful(const char* op_type, TF_Status* status) {
  const tensorflow::OpRegistrationData* op_reg_data;
  status->status =
      tensorflow::OpRegistry::Global()->LookUp(op_type, &op_reg_data);
  if (!status->status.ok()) {
    return 0;
  }

  TF_Buffer* buffer = TF_NewBuffer();

  TF_GraphGetOpDef(graph, "Add", buffer, status);
  ASSERT_EQ(TF_OK, TF_GetCode(status));
  const OpDef* expected_op_def;
  TF_ASSERT_OK(OpRegistry::Global()->LookUpOpDef("Add", &expected_op_def));
  std::string expected_serialized;
  expected_op_def->SerializeToString(&expected_serialized);
  std::string actual_string(reinterpret_cast<const char*>(buffer->data),