// a deterministic serialization and fingerprint. Other sources of
  // nondeterminism include unstable node ordering.
  SortControlInputs(&def);

  std::string s;
  if (!SerializeToStringDeterministic(def, &s)) {
    return errors::Internal("Failed to serialize graphdef.");
  }
  return s;
}

absl::StatusOr<uint64> FingerprintGraph(const Graph& graph) {

  string s1, s2;
  tensorflow::FunctionDef fdef1, fdef2;
  ASSERT_TRUE(GetFunctionDef(f1, &fdef1));
  ASSERT_TRUE(GetFunctionDef(f2, &fdef2));
  SerializeToStringDeterministic(fdef1, &s1);
  SerializeToStringDeterministic(fdef2, &s2);
  ASSERT_EQ(s1, s2);
}

string GetName(TF_Function* func) {
  tensorflow::FunctionDef fdef;
  GetFunctionDef(func, &fdef);