def _query_label(self, x: np.ndarray) -> np.ndarray:
        """
        Query the victim classifier.

        :param x: An array with the source input to the victim classifier.
        :return: Target values (class labels) one-hot-encoded of shape (nb_samples, nb_classes).
        """
        labels = self.estimator.predict(x=x, batch_size=self.batch_size_query)
        if not self.use_probability:
            labels = np.argmax(labels, axis=1)
            labels = to_categorical(labels=labels, nb_classes=self.estimator.nb_classes)

        return labels

        Query the victim classifier.

        :param x: An array with the source input to the victim classifier.
        :return: Target values (class labels) one-hot-encoded of shape (nb_samples, nb_classes).
        
art/attacks/extraction/copycat_cnn.py