永辉超市 = {
    ‘食品饮料‘:{
        ‘休闲食品‘:{
            ‘坚果‘:[‘山核桃‘,‘腰果‘],
            ‘炒货‘:[‘瓜子‘,‘花生‘]
        },
        ‘牛奶‘:{
            ‘进口牛奶‘:[‘安慕希‘,‘欧德堡‘],
            ‘国产牛奶‘:[‘伊利‘,‘蒙牛‘]
        },
        ‘饮料‘:{
            ‘碳酸饮料‘:[‘芬达‘,‘雪碧‘],
            ‘咖啡‘:[‘星巴克‘,‘雀巢‘]
        }
    },
    ‘粮油副食‘:{
        ‘食用油‘:{
            ‘菜籽油‘:[‘鲁花‘,‘福临门‘],
            ‘玉米油‘:[‘金龙鱼‘,‘长寿花‘]
        },
        ‘米面‘:{
            ‘大米‘:[‘东北长粒‘,‘汉中大米‘],
            ‘面粉‘:[‘特一粉‘,‘优质粉‘]
        },
        ‘厨房调味‘:{
            ‘酱油‘:[‘海天‘,‘老抽‘],
            ‘食盐‘:[‘加碘食盐‘,‘无碘食盐‘]
        }
    },
    ‘个人护理‘:{
        ‘洗发护发‘:{
            ‘洗发‘:[‘潘婷‘,‘沙宣‘],
            ‘护发‘:[‘蜂花‘,‘惠润‘]
        },
        ‘身体‘:{
            ‘润肤‘:[‘韩国所望‘,‘妮维雅‘,‘凡士林‘],
            ‘沐浴‘:[‘雅蜜‘,‘安安‘,‘多芬‘]
        },
        ‘口腔‘:{
            ‘牙膏‘:[‘佳洁士‘,‘黑人‘,‘安利‘],
            ‘漱口水‘:[‘李施德林‘,‘皓乐齿‘,‘比那氏‘]
        }
    }
}
print("Welcom to 永辉超市，我们有以下热销商品")
while True:
    for level1 in 永辉超市 :
        print("\t",level1)
    user_choice1 = input("please enter your choice1:")
    if user_choice1.strip() in 永辉超市:
        while True:
            for level2 in 永辉超市[user_choice1]:
                print("\t\t",level2)
            user_choice2 = input("please enter your choice2:")
            if user_choice2.strip() in 永辉超市[user_choice1]:
                while True:
                    for level3 in 永辉超市[user_choice1][user_choice2]:
                        print("\t\t\t", level3)
                    user_choice3 = input("please enter your choice3:")
                    if user_choice3 in 永辉超市[user_choice1][user_choice2]:
                        for level4 in 永辉超市[user_choice1][user_choice2][user_choice3]:
                            print("\t\t\t", level4)
                        user_choice4 = input("最后一级，按b返回上一级，按q退出:")
                        if user_choice4 == ‘b‘:
                            pass
                    elif user_choice3 == ‘b‘:
                        break
                    else:
                        user_choice3 == ‘q‘
                        exit()
            elif user_choice2 == ‘b‘:
                break
            else:
                user_choice2 == ‘q‘
                exit()
    else:
        user_choice1 == ‘q‘
        exit()

Welcom to 永辉超市，我们有以下热销商品
     个人护理
     粮油副食
     食品饮料
please enter your choice1:个人护理
         口腔
         身体
         洗发护发
please enter your choice2:口腔
             牙膏
             漱口水
please enter your choice3:牙膏
             佳洁士
             黑人
             安利
最后一级，按b返回上一级，按q退出:b
             牙膏
             漱口水
please enter your choice3:b
         口腔
         身体
         洗发护发
please enter your choice2:b
     个人护理
     粮油副食
     食品饮料
please enter your choice1:q