TF_ImportGraphDefOptions* opts = TF_NewImportGraphDefOptions();
  TF_GraphImportGraphDef(graph, graph_def, opts, s);
  ASSERT_EQ(TF_OK, TF_GetCode(s)) << TF_Message(s);

  TF_Operation* scalar = TF_GraphOperationByName(graph, "scalar");

  // Import it in a fresh graph with an unused input mapping.
  TF_DeleteImportGraphDefOptions(opts);
  opts = TF_NewImportGraphDefOptions();

  {
    mutex_lock l(graph->mu);
    versions = graph->graph.versions();
  }
  status->status = MessageToBuffer(versions, output_version_def);
}

TF_ImportGraphDefOptions* TF_NewImportGraphDefOptions() {
  return new TF_ImportGraphDefOptions;
}
void TF_DeleteImportGraphDefOptions(TF_ImportGraphDefOptions* opts) {
  delete opts;
}

// TF_ImportGraphDefOptions holds options that can be passed to
// TF_GraphImportGraphDef.
typedef struct TF_ImportGraphDefOptions TF_ImportGraphDefOptions;

TF_CAPI_EXPORT extern TF_ImportGraphDefOptions* TF_NewImportGraphDefOptions(
    void);
TF_CAPI_EXPORT extern void TF_DeleteImportGraphDefOptions(
    TF_ImportGraphDefOptions* opts);

// Set the prefix to be prepended to the names of nodes in `graph_def` that will