Three-level menu Python notation (recursive notation)

 data structure: Menu = {' Beijing ': {' Haidian ': {' Five crossings ': {' Soho ': {}, ' NetEase                ': {}, ' Google ': {}}, ' Zhongguancun ': {' Iqiyi ': {}, ' Autohome ': {},            ' Youku ': {},}, ' on the ground ': {' Baidu ': {},},}, ' Changping ': {        ' Shahe ': {' old boy ': {}, ' Beihang ': {},}, ' Tian Tong Yuan ': {}, ' Huilongguan ': {},            }, ' Chaoyang ': {}, ' Dongcheng ': {},}, ' Shanghai ': {' Minhang ': {' People's Square ': {' Fried chicken Shop ': {} }}, ' Zhabei ': {' rail war ': {' Ctrip ': {}}}, ' Pudong ': {},}, ' Shandong ': { },} 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 
 Reference Code is as follows: 

 # coding:utf-8 
 #!/usr/bin/env python3 
 Menu = {
 ' Beijing ': {
 ' Haidian ': {
 ' five crossings ': {
 ' Soho ': {}, 
 ' NetEase ': {}, 
 ' Google ': {} 
}, 
 ' Zhongguancun ': { ' Iqiyi art ': {}, 
 ' Autohome ': {}, 
 ' Youku ': {}, 
}, 
                ' Land ': {
 ' Baidu ': {}, 
}, 
}, 
 ' Changping ': {
 ' Shahe ': {
 ' Old boy ': {}, 
 ' Beihang ': {}, 
}, 
 ' Tian Tong Yuan ': {}, 
 ' Huilongguan ': {}, 
}                , 
 ' Chaoyang ': {}, 
 ' Dongcheng ': {}, 
}, 
 ' Shanghai ': {
 ' Minhang ': {
 ' People's Square ': {
            ' Fried Chicken Shop ': {} 
} 
}, 
 ' Zhabei ': {
 ' train war ': {
 ' Ctrip ': {} 
 } 
}, 
 ' Pudong ': {}, 
}, 
 ' Shandong ': {}, 
} 
 #递归方式实现 

def show_menu (CH):
    For s in CH:
        Print (s)
    Print (' Return/exit ')
    p = input (' You select Yes ')
    if p = = ' exit ':
        Exit ()
    elif p = = ' return ':
        Return
    Else
        If p in Ch:
            Show_menu (Ch[p])
        Show_menu (CH)
Show_menu (Menu)

Three-level menu Python notation (recursive notation)