or just use the newly added multi class roc auc metric https://forums.fast.ai/t/discrepancy-with-proba-based-metrics-between-fastai2-and-sklearn/70215/43?u=frapochetti 
or just use the newly added multi class roc auc metric https://forums.fast.ai/t/discrepancy-with-proba-based-metrics-between-fastai2-and-sklearn/70215/43?u=frapochetti