def split_array_as_list(self, values):
        """Group values as a list of arrays, or a jagged-array

        Parameters
        ----------
        values : ndarray, [keys, ...]

        Returns
        -------
        list of length self.groups of ndarray, [key_count, ...]
        """
        values = np.asarray(values)
        values = values[self.index.sorter]
        return np.split(values, self.index.slices[1:-1], axis=0)