共享流量包新年活动

class TrafficPackage:
    def __init__(self, size, expiration_date):
        self.size = size  # 流量包大小（MB）
        self.expiration_date = expiration_date  # 过期日期

class User:
    def __init__(self, name, used_traffic=0):
        self.name = name
        self.used_traffic = used_traffic
        self.traffic_packages = []

    def add_package(self, package):
        self.traffic_packages.append(package)

    def use_traffic(self, amount):
        if amount <= self.available_traffic():
            self.used_traffic += amount
            for pkg in self.traffic_packages:
                if pkg.size >= amount:
                    pkg.size -= amount
                    break
        else:
            print("Not enough traffic available.")

    def available_traffic(self):
        return sum(pkg.size for pkg in self.traffic_packages)

# 示例使用
user1 = User("Alice")
pkg1 = TrafficPackage(500, "2024-01-01")
user1.add_package(pkg1)
user1.use_traffic(200)
print(f"{user1.name} has {user1.available_traffic()} MB left.")