增值电信优惠卷

class Order:
    def __init__(self, total_amount):
        self.total_amount = total_amount
        self.coupon = None

    def apply_coupon(self, coupon_code):
        # 假设有一个函数来验证和应用优惠券
        self.coupon = validate_and_apply_coupon(coupon_code)

    def calculate_final_amount(self):
        if self.coupon:
            return self.total_amount - self.coupon.discount
        return self.total_amount

def validate_and_apply_coupon(coupon_code):
    # 这里应该是与数据库或外部服务交互来验证优惠券
    # 假设返回一个Coupon对象
    return Coupon(discount=10)  # 示例中直接返回10元折扣

class Coupon:
    def __init__(self, discount):
        self.discount = discount

# 使用示例
order = Order(total_amount=100)
order.apply_coupon("SAVE10")
final_amount = order.calculate_final_amount()
print(f"Final amount after coupon: {final_amount}")