def METHOD_NAME(self, x: np.ndarray, y: np.ndarray, **kwargs) -> np.ndarray:
    """
    Compute the loss of the neural network for samples `x`.
    :param x: Samples of shape (nb_samples, nb_features) or (nb_samples, nb_pixels_1, nb_pixels_2,
              nb_channels) or (nb_samples, nb_channels, nb_pixels_1, nb_pixels_2).
    :param y: Target values (class labels) one-hot-encoded of shape `(nb_samples, nb_classes)` or indices
              of shape `(nb_samples,)`.
    :return: Loss values.
    :rtype: Format as expected by the `model`
    """
    raise NotImplementedError