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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 get_amount_arrears_transactions(self, billing_cycle):
 """Get the sum of all transaction legs in to_account during given billing cycle"""

        previous_billing_cycle = billing_cycle.get_previous()
        if not previous_billing_cycle:
            return Decimal(0)
        return self.to_account.balance(
            transaction__date__lt=previous_billing_cycle.date_range.upper,
            transaction__date__gte=previous_billing_cycle.date_range.lower,
        )