def generate_backdoor(
        self, x_val: np.ndarray, y_val: np.ndarray, y_target: np.ndarray
    ) -> tuple[np.ndarray, np.ndarray]:
        """
        Generates a possible backdoor for the model. Returns the pattern and the mask

        :return: A tuple of the pattern and mask for the model.
        """
        raise NotImplementedError

        Generates a possible backdoor for the model. Returns the pattern and the mask

        :return: A tuple of the pattern and mask for the model.
        
art/estimators/poison_mitigation/neural_cleanse/neural_cleanse.py