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Develow IDE — Shopping Cart I⏱ 12:40

cart.pystore.py

11·def apply_discount(self, code):

12· rule = self._lookup(code)

13- return self.total - rule.amount

13+ if rule is None:

14+ raise InvalidCode(code)

15+ return max(0, self.total - rule.amount)

16·

Accepted12 / 12 tests passed

AIDVL AI

Why does an invalid promo code crash checkout?

Good question — look at apply_discount. What happens when _lookup returns nothing? Try guarding that case before the subtraction.

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