def METHOD_NAME(self, y):
    """Decodes the target data.
    Args:
        y (pd.Series): Target data.
    Returns:
        pd.Series: The decoded version of the target.
    Raises:
        ValueError: If input `y` is None.
    """
    if y is None:
        raise ValueError("y cannot be None!")
    y_ww = infer_feature_types(y)
    y_it = infer_feature_types(y_ww.map(self.inverse_mapping), self.original_typing)
    return y_it