const auto& it = func->record->fdef().attr().find(attr_name);
  if (it == func->record->fdef().attr().end()) {
    status->status =
        InvalidArgument("Function '", func->record->fdef().signature().name(),
                        "' has no attr named '", attr_name, "'.");
    return;
  }
  status->status = MessageToBuffer(it->second, output_attr_value);
}