About the error "auto" not allowed in function prototype in libtorch

Hi, All

I have met an issue in libtorch when I use auto as the type for unlabel dataset as the input argument of the function.
The error is " “auto” not allowed in function prototype"

The context is:

function1(auto &unlabel)
torch::Tensor Unlabelset(){
auto raw_dataset= torch::data::datasets::MNIST("…/data", torch::data::datasets::MNIST::Mode::kTrain).map(torch::data::transforms::Normalize<>(0.13707,0.3081)).map(torch::data::transforms::Stack<>());

Another issue is that it seems that the function Unlabelset() is not recognized even if I define it explicitly. Any comments or suggestions ?

Many thanks.