code: def hs_indices(self):
          
          if self.dimension_type in {DT.MR_CAT, DT.LOGICAL}:
              return ()
  
          return tuple(
              (subtotal.anchor_idx, subtotal.addend_idxs) for subtotal in self._subtotals
          )
docs: tuple of (anchor_idx, addend_idxs) pair for each subtotal.
  
          Example::
  
              (
                  (2, (0, 1, 2)),
                  (3, (3,)),
                  ('bottom', (4, 5))
              )
  
          Note that the `anchor_idx` item in the first position of each pair
          can be 'top' or 'bottom' as well as an int. The `addend_idxs` tuple
          will always contains at least one index (a subtotal with no addends
          is ignored).