Python implementation level Three menu

Requirements:    You can choose to go to each submenu    from any level back to the previous layer    you can exit the program from any level    required new knowledge points: List, dictionary
    Use only one while loop

1 #!-*-coding:utf-8-*-2 3menu = {4     'Beijing': {5         'Haidian': {6             'Five crossing': {7                 'Soho': {},8                 'NetEase': {},9                 'Google': {}Ten             }, One             'Zhongguancun': { A                 'Iqiyi Art': {}, -                 'Autohome': {}, -                 'Youku': {}, the             }, -             'on the ground': { -                 'Baidu': {}, -             }, +         }, -         'changping': { +             'Shahe': { A                 'old boy': {}, at                 'Beihang University': {}, -             }, -             'Tin Tong Court': {}, -             'Huilongguan': {}, -         }, -         'Chaoyang': {}, in         'Dongcheng': {}, -     }, to     'Shanghai': { +         'Minhang': { -             "People's square": { the                 'Fried Chicken Shop': {} *             } $         },Panax Notoginseng         'Zhabei': { -             'Train Warfare': { the                 'Ctrip': {} +             } A         }, the         'Pudong': {}, +     }, -     'Shandong': {}, $ } $Current_layer = Menu#Implementing Dynamic Loops -Parent_layer = []#Keep all parent layers, and the last element is always the parent -  the  whileTrue: -     Print('-'* 10,"Menu",'-'* 10)Wuyi      forIinchCurrent_layer:#traverse the print address the         Print(i) -     Print("Please enter the menu name below, or B: Return to the previous layer, Q: Exit \ n",'-'* 26) WuChoice = input (">>>"). Strip () -     ifChoiceinchCurrent_layer: About         ifCurrent_layer[choice]:#determine if the final layer $Parent_layer.append (Current_layer)#Add the current layer as the parent layer before entering the child layer -Current_layer = Current_layer[choice]#Modify a child layer -         Else: -             Print('current is the last page') A     elifChoice = ="': +         Continue the     elifChoice = ='b' orChoice = ='B':#back to top -         ifParent_layer:#determine if the Parent_layer is empty $Current_layer = Parent_layer.pop ()#Remove the current layer parent layer the     #Exit Loop the     elifChoice = ='Q' orChoice = ='Q': the          Break the     Else: -         Print("\033[34;1m input Error, please re-enter \033[0m")

Python implementation level Three menu