GraphDef graph_def;
  graph.ToGraphDef(&graph_def);
  if (!function_library) return failure();
  for (const std::string& func_name :
       function_library->ReachableDefinitions(graph_def).ListFunctionNames()) {
    const FunctionDef* func_def = function_library->Find(func_name);
    std::unique_ptr<FunctionBody> func_body;
    absl::Status status = FunctionDefToBodyHelper(