TF_ImportGraphDefOptionsAddInputMapping(opts, "scalar", 0, {scalar, 0});
  TF_ImportGraphDefOptionsAddReturnOutput(opts, "feed", 0);
  TF_ImportGraphDefOptionsAddReturnOutput(opts, "scalar", 0);
  EXPECT_EQ(2, TF_ImportGraphDefOptionsNumReturnOutputs(opts));
  TF_ImportGraphDefOptionsAddReturnOperation(opts, "scalar");
  EXPECT_EQ(1, TF_ImportGraphDefOptionsNumReturnOperations(opts));
  tensorflow::GraphDef graph_def_proto;

  opts->tensor_id_data.push_back(oper_name);
  const string& oper_name_str = opts->tensor_id_data.back();
  opts->opts.return_tensors.emplace_back(oper_name_str, index);
}

int TF_ImportGraphDefOptionsNumReturnOutputs(
    const TF_ImportGraphDefOptions* opts) {
  return opts->opts.return_tensors.size();
}

void TF_ImportGraphDefOptionsAddReturnOperation(TF_ImportGraphDefOptions* opts,