Multiclass Naive Bayes with probabilities for y

Hi, I've got to train a classifier where a sample can belong to one of many classes. And the training set output is given as the probability for belonging that sample to each class. Eg: sample#1 : C1-0.6, C2-0.4, C3-0.0

I'm planning to use a Naive Bayes classifier using Scikit-learn. I couldn't find a fit method in naive_bayes.py which takes probability for each class for training.