int arg_index = iter->second;
  if (inserted) {
    NodeDef arg_def;
    NodeDefBuilder builder(
        absl::StrCat(src_node->name(), "_", src_slot, "_arg"), kArgOp,
        NodeDebugInfo(src_node->def()));
    DataType dtype = edge->dst()->input_type(edge->dst_input());
    builder.Attr("T", dtype);
    builder.Attr("index", arg_index);
    Status s = builder.Finalize(&arg_def);