pickle5.pickle.PicklingError: Could not pickle object as excessively deep recursion required

pickle5.pickle.PicklingError: Could not pickle object as excessively deep recursion required.

Got this error when running a simple tuning task based on PyTorch.

Ray version: 1.7.1
Python version: 3.6.5
pickle5 version: 0.0.11
PyTorch version: 1.9.0

Do you have a repro script?