I work on python 3.6.5 and sklearn 0.19.1 on conda 4.5.11. According to this [post](https://stackoverflow.com/questions/42920148/using-sklearn-voting-ensemble-with-partial-fit), I am surprised that voting classifiers do not accept `prefix` classifiers. May I know is it because it is unnecessary from your respective or it was purely short of hand? Thank you very much.