docs: def _subperiod_tick(self, current_interval, intervals):
          """Tick each sub-period, copying group_decisions to subperiod_group_decisions.""" 
          self.refresh_from_db()
          for key, value in self.group_decisions.items():
              self.subperiod_group_decisions[key] = value
          self.send('group_decisions', self.subperiod_group_decisions)
          self.save(update_fields=['subperiod_group_decisions'])