GraphDefBuilder b(GraphDefBuilder::kFailImmediately);
  Scope root = Scope::NewRootScope().ExitOnError();
  FunctionDefLibrary library;

  FunctionDef identity_func = FunctionDefHelper::Create(
      "IdentityFunc",
      /*in_def=*/{"x:float"},
      /*out_def=*/{"res:float"},
      /*attr_def=*/{},
      /*node_def=*/{{{"t0"}, "Identity", {"x"}, {{"T", DT_FLOAT}}}},
      /*ret_def*/ {{"res", "t0:output"}});