auto builder = NodeBuilder(unique_name, "_SwitchN")
                     .Input(_data)
                     .Input(_output_index)
                     .Attr("num_outs", num_outs);
  scope.UpdateBuilder(&builder);
  scope.UpdateStatus(builder.Finalize(scope.graph(), &ret));
  if (!scope.ok()) return;
  scope.UpdateStatus(scope.DoShapeInference(ret));
  for (int32_t i = 0; i < ret->num_outputs(); ++i) {