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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 _is_finished(self, as_of):
 """Have the specified number of billing cycles been completed? If so, we should not be enacting this RecurringCost. """

        if self.is_one_off():
            last_billing_cycle = self.get_billing_cycles()[self.total_billing_cycles - 1]
            return last_billing_cycle.date_range.upper <= as_of
        else:
            return False