WARNING Trial Runner checkpointing failed: cannot pickle 'dict_values' object

[einarG-1qbit]

Hi,
I'm training a custom sklearn model with tune-sklearn and skopt Bayesian.
All works fine, except that in my logs I get the warning:
WARNING Trial Runner checkpointing failed: cannot pickle 'dict_values' object
No other info is provided, just the warning. How do I fix this issue?

I use:
tune-sklearn 0.2.1
ray 1.2.0
sklearn 0.0

I had few session crashes on GCP and I tried to restore the state from ray, however no checkpoints were found.
I guess this pertains to the warning above.

[Yard1]

Does it happen with a different search algo?

[richardliaw]

I think checkpoint/restore may not work directly with tune-sklearn. However, I would try:

tune-sklearn (latest master, so clone off of github)
pip install ray ==1.3

[einarG-1qbit]

thanks for the quick reply.
I just tried TuneSearchCV without the parameter search_optimization (default random search)
And there weren't any warnings.