测试服务新年优惠活动

class Promotion:
    def __init__(self, name, discount_rate, start_date, end_date):
        self.name = name
        self.discount_rate = discount_rate
        self.start_date = start_date
        self.end_date = end_date

    def is_valid(self, current_date):
        return self.start_date <= current_date <= self.end_date

def apply_promotion(promotions, service_cost, current_date):
    for promo in promotions:
        if promo.is_valid(current_date):
            return service_cost * (1 - promo.discount_rate)
    return service_cost

# 示例使用
promotions = [
    Promotion("春节特惠", 0.2, "2023-01-20", "2023-02-05"),
    Promotion("新年套餐", 0.15, "2023-01-01", "2023-01-15")
]

current_date = "2023-01-25"
service_cost = 1000

final_cost = apply_promotion(promotions, service_cost, current_date)
print(f"最终费用: {final_cost}")