数据库扩展首购活动

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

    def is_eligible(self, user):
        # 这里可以添加具体的资格判断逻辑
        return user.is_new and user.registration_date <= self.duration

class User:
    def __init__(self, username, is_new, registration_date):
        self.username = username
        self.is_new = is_new
        self.registration_date = registration_date

# 示例用法
new_user = User(username="john_doe", is_new=True, registration_date="2023-01-01")
promotion = Promotion(name="First Purchase", discount_rate=0.2, duration="2023-12-31")

if promotion.is_eligible(new_user):
    print(f"{new_user.username} 符合 {promotion.name} 活动资格，可享受 {promotion.discount_rate*100}% 折扣！")
else:
    print(f"{new_user.username} 不符合 {promotion.name} 活动资格。")