• https://lgtm.com/projects/g/scikit-learn/scikit-learn/snapshot/1a981e87ba6f8d66ecfd6940184836446ded3f4c/files/sklearn/ensemble/bagging.py#L778
• https://lgtm.com/projects/g/scikit-learn/scikit-learn/snapshot/1a981e87ba6f8d66ecfd6940184836446ded3f4c/files/sklearn/multiclass.py#L726

These error cases are clearly not well tested atm.

H/T: lgtm.com