@staticmethod
def _get_total_mapping():
    """Inverse operation of :meth:`._map_preds`

        This is called after reading back predictions from disk to create
        confusion matrices. This must be overridden if :meth:`_map_preds`
        is also overridden.

        :return: A dictionary mapping each prediction in .csv to an integer
        :rtype: dict

        .. seealso:: :class:`deepsleep.models.SpindleModel`
        """
    return {}
