def __init__(self, feature_extractor, train_classifier, eval_classifier):
        """
        :param feature_extractor: a differentiable feature extractor
        :param train_classifier: a differentiable classifier used
            during training
        :param eval_classifier: a classifier used during testing.
            Doesn't have to be differentiable.
        """
        super().__init__()
        self.feature_extractor = feature_extractor
        self.train_classifier = train_classifier
        self.eval_classifier = eval_classifier

        :param feature_extractor: a differentiable feature extractor
        :param train_classifier: a differentiable classifier used
            during training
        :param eval_classifier: a classifier used during testing.
            Doesn't have to be differentiable.
        
avalanche/models/dynamic_modules.py