class EnsembleClassifier(BaseEstimator, ClassifierMixin):

    def __init__(self, classifiers=None):
        self.classifiers = classifiers

def fit(self, X, y):
    for classifier in self.classifiers:
        classifier.fit(X, y)

def predict_proba(self, X):
    self.predictions_ = list()
for classifier in self.classifiers:
    pass
Best way to combine probabilistic classifiers in scikit-learn