A logo can represent a certain operation (three complete menu and exit all cycles code)

#!/user/bin/python
# -*- coding:utf-8 -*-
tag = True
while tag:
    print("leve1")
    choice = input("level1>>:").strip()
    if choice == "quit" : break
    if choice == "quit_all" : tag = False
    while tag:
        print("level2")
        choice = input("level2>>:").strip()
        if choice == "quit" : break
        if choice == "quit_all" : tag = False
        while tag:
            print("level3")
            choice = input("level3>>:").strip()
            if choice == "quit" : break
            if choice == "quit_all":tag = False