def METHOD_NAME(
    self, x: "tf.Tensor", y: Optional["tf.Tensor"], **kwargs
) -> Tuple["tf.Tensor", Optional["tf.Tensor"]]:
    """
    Internal method implementing the transformation per input sample.
    :param x: Input samples.
    :param y: Label of the samples `x`.
    :return: Transformed samples and labels.
    """
    raise NotImplementedError