CHECK_EQ(TF_OK, TF_GetCode(status)) << TF_Message(status);
    TFE_Execute(op, &h, &num_retvals, status);
    CHECK_EQ(TF_OK, TF_GetCode(status)) << TF_Message(status);
    CHECK_EQ(1, num_retvals);
    CHECK(h);
    CHECK_EQ(TF_FLOAT, TFE_TensorHandleDataType(h));
    CHECK_EQ(0, TFE_TensorHandleNumDims(h, status));
    CHECK_EQ(TF_OK, TF_GetCode(status)) << TF_Message(status);
    h = nullptr;
    TFE_DeleteOp(op);
  }

  TF_DeviceList* device_list = list.get();

  CHECK_EQ(TF_OK, TF_GetCode(s)) << TF_Message(s);

  const int num_devices = TF_DeviceListCount(device_list);
  LOG(INFO) << "There are " << num_devices << " devices.";
  for (int i = 0; i < num_devices; ++i) {
    const char* device_name = TF_DeviceListName(device_list, i, s);
    CHECK_EQ(TF_OK, TF_GetCode(s)) << TF_Message(s);