code: def indices(self):
          
          if len(self.groupings) == 1:
              return self.groupings[0].indices
          else:
              label_list = [ping.labels for ping in self.groupings]
              keys = [com.values_from_object(ping.group_index)
                      for ping in self.groupings]
              return get_indexer_dict(label_list, keys)
docs: dict {group name -> group indices}