def _pickle_classifier(classifier: "CLASSIFIER_NEURALNETWORK_TYPE", file_name: str) -> None:
        """
        Pickles the self.classifier and stores it using the provided file_name in folder `art.config.ART_DATA_PATH`.

        :param classifier: Classifier to be pickled.
        :param file_name: Name of the file where the classifier will be pickled.
        """
        full_path = os.path.join(config.ART_DATA_PATH, file_name)
        folder = os.path.split(full_path)[0]
        if not os.path.exists(folder):
            os.makedirs(folder)

        with open(full_path, "wb") as f_classifier:
            pickle.dump(classifier, f_classifier)

        Pickles the self.classifier and stores it using the provided file_name in folder `art.config.ART_DATA_PATH`.

        :param classifier: Classifier to be pickled.
        :param file_name: Name of the file where the classifier will be pickled.
        
art/defences/detector/poison/activation_defence.py