'Validate X whenever one tries to predict, apply, predict_proba'

def _validate_X_predict(self, X):

    if ((self.estimators_ is None) or (len(self.estimators_) == 0)):
        raise NotFittedError('Estimator    not    fitted,    call    `fit`    before    exploiting    the    model.')
    return self.estimators_[0]._validate_X_predict(X, check_input=True)
