帮忙解决一下bug

问题描述：加了一个每日‘集五福’上限，即规定每天获取到的福字卡片总数不得超过十张，否则就要等到第二天才能继续进行‘集五福’获取福字卡片。可没有达到预期效果，定义的self.cards用来计算每天获取的福字卡片总数，一直为0。

​# coding:utf-8

"""
集五福，迎新春
"""
import random
import time


class Chances(object):
    list_chance = []

    def __init__(self):
        for i in range(0, 90):
            self.list_chance.append(0)
        for i in range(0, 5):
            self.list_chance.append(1)
        for i in range(0, 3):
            self.list_chance.append(2)
        self.list_chance.append(3)
        self.list_chance.append(4)


class Blessings(Chances):
    cards = 0
    money = 0
    _blessings = 0
    happy = {
        "1": {"name": "富强福", "num": 0},
        "2": {"name": "和谐福", "num": 0},
        "3": {"name": "友善福", "num": 0},
        "4": {"name": "爱国福", "num": 0},
        "5": {"name": "敬业福", "num": 0}
    }

    def draw(self, start):
        if isinstance(start, str):
            number = random.randint(1, 5)
            for k, v in self.happy.items():
                if str(number) == k:
                    v["num"] = v["num"] + 1
                    print("获取到: {}".format(v["name"]))

    # 规定每天获取到的福字卡片总数不得超过十张
    def check_blessings(self):
        for k, v in self.happy.items():
            self.cards += v['num']
        if self.cards == 11:
            print('=' * 20)
            raise Exception('每日最多可获取{}张福'.format(self.cards - 1))

    def show(self):
        print("当前拥有的福:")
        for k, v in self.happy.items():
            print(v["name"], ":", v["num"])

    def service_list(self):
        service_list = {
            1: '按下<Enter>键集五福',
            2: '按下<s>键查看获取福字',
            3: '按下<c>合成五福',
            4: '按下<d>抽红包',
            5: '按下<q>退出'
        }
        for k, v in service_list.items():
            print(v)

    def cheak(self):
        for k, v in self.happy.items():
            if v['num'] > 0:
                flag = True
            else:
                flag = False
                break
        return flag

    def collect(self):
        if self.cheak():
            self._blessings += 1
            print('当前合成{}张五福'.format(self._blessings))
            for k, v in self.happy.items():
                v['num'] -= 1
        else:
            print('当前合成{}张五福'.format(self._blessings))
            for k, v in self.happy.items():
                if v['num'] == 0:
                    print('缺少{}'.format(v['name']))
            print('你的福不足！')
            print('=' * 20)

    def draw_cash(self):
        if self._blessings > 0:
            money_flag = random.choice(self.list_chance)
            if money_flag == 0:
                _money = random.randint(1, 5)
            elif money_flag == 1:
                _money = random.randint(1000, 1999)
            elif money_flag == 2:
                _money = random.randint(2000, 4999)
            elif money_flag == 3:
                _money = random.randint(5000, 9999)
            elif money_flag == 4:
                _money = random.randint(10000, 20000)
            print('抽中红包金额{}'.format(_money))
            self.money += _money
            print('红包总金额{}'.format(self.money))
            self._blessings -= 1
        else:
            print('五福不足！')
            print('=' * 20)

    def run(self):
        while True:
            self.service_list()
            start = input("请选择：")
            if start == '':
                if self.cards <= 10:
                    self.draw(start)
                else:
                    try:
                        self.check_blessings()
                    except Exception as e:
                        print(e)
                print('=' * 20)
            elif start == 's':
                self.show()
                print('=' * 20)
            elif start == 'c':
                print('=' * 20)
                self.collect()
            elif start == 'q':
                print('感谢使用，再见！')
                print('=' * 20)
                break
            elif start == 'd':
                print('=' * 20)
                self.draw_cash()
            else:
                print('输入有误，重新输入！')
                print('=' * 20)


if __name__ == '__main__':
    b = Blessings()
    b.run()