Session* session;
  status->status = NewSession(opt->options, &session);
  if (status->status.ok()) {
    TF_Session* new_session = new TF_Session(session, graph);
    if (graph != nullptr) {
      mutex_lock l(graph->mu);
      graph->sessions[new_session] = "";
    }
    return new_session;
  } else {
    LOG(ERROR) << status->status;
    DCHECK_EQ(nullptr, session);
    return nullptr;
  }
}