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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_billing_complete(self):
 """Has the specified `fixed_amount` been billed? If so, we should not be enacting this RecurringCost. """

        if self.is_one_off():
            return self.get_billed_amount() >= Balance(self.fixed_amount, self.currency)
        else:
            return False