// the graph def function library.
  for (const FunctionDef& function :
       bundle.meta_graph_def().graph_def().library().function()) {
    std::unique_ptr<TFConcreteFunction> concrete_function;
    TF_RETURN_IF_ERROR(TFConcreteFunction::Create(/*function_def=*/&function,
                                                  /*captures=*/{},
                                                  /*metadata=*/{},