ASSERT_TRUE(TF_GraphOperationByName(graph, "feed") != nullptr);
  TF_Operation* oper = ScalarConst(3, graph, s);
  ASSERT_EQ(TF_OK, TF_GetCode(s)) << TF_Message(s);
  ASSERT_TRUE(TF_GraphOperationByName(graph, "scalar") != nullptr);
  Neg(oper, graph, s);
  ASSERT_EQ(TF_OK, TF_GetCode(s)) << TF_Message(s);
  ASSERT_TRUE(TF_GraphOperationByName(graph, "neg") != nullptr);

  // Export to a GraphDef.

    }
  }

  TF_Operation* enqueue_op = TF_GraphOperationByName(
      session->graph,
      tensorflow::strings::StrCat("fifo_queue_enqueue_", tensor_id).c_str());
  if (enqueue_op == nullptr) {
    status->status = tensorflow::errors::Internal(
        "Unable to find the enqueue node in the TF graph.");
    return;
  }

  TF_Operation* placeholder_op = TF_GraphOperationByName(
      session->graph,

  if (g == nullptr) return;
  g->mu.lock();
  g->delete_requested = true;
  const bool del = g->sessions.empty();
  g->mu.unlock();
  if (del) delete g;
}

TF_Operation* TF_GraphOperationByName(TF_Graph* graph, const char* oper_name) {
  mutex_lock l(graph->mu);
  auto iter = graph->name_map.find(oper_name);
  if (iter == graph->name_map.end()) {
    return nullptr;
  } else {