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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 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'])