三级菜单：

data={
    ‘Beijing‘:{
        ‘Changping‘:{
            ‘shahe1‘:[‘cook1‘,‘book1‘],
            ‘tiantongyuan1‘:[‘TV1‘,‘IPAD1‘]
        },
        ‘Chaoyang‘:{
            ‘shahe2‘: [‘cook2‘, ‘book2‘],
            ‘tiantongyuan1‘:[‘TV1‘,‘IPAD1‘]
        },
    },
    ‘Jiangsu‘:{
        ‘Xuzhou‘:{
            ‘Suining‘:[‘goverment1‘,‘department1‘],
            ‘Tongshan‘:[‘goverment2‘,‘department2‘]
        },
        ‘Nanjing‘: {
            ‘Liuhe‘: [‘goverment1‘, ‘department1‘],
            ‘Lishui‘: [‘goverment2‘, ‘department2‘]
        },
    },
}

exit_flag=False

while not exit_flag:
    for i1 in data:
        print(i1)
    choice=input("choose1>>:")
    if choice in data:
        while not exit_flag:
            for i2 in data[choice]:
                print("t",i2)
            choice2=input("choose2>>:")
            if choice2 in data[choice]:
                while not exit_flag:
                    for i3 in data[choice][choice2]:
                        print("tt",i3)
                    choice3=input("choose3>>:")
                    if choice3 in data[choice][choice2]:
                        while not exit_flag:
                            for i4 in data[choice][choice2][choice3]:
                                print("ttt",i4)
                            choice4=input("Press b to return the last level>>:")
                            if choice4 == "b":
                                break
                            elif choice4=="q":
                                exit_flag = True
                    if choice3 == "b":
                         break
                    elif choice3 == "q":
                        exit_flag = True
            if choice2 == "b":
                break
            elif choice2 == "q":
                exit_flag = True
    elif choice == "q":
        exit_flag = True