python:practice Advanced three-level menu

menu={'jx':{'shangrao':{'yiyang':{'zuoshenwei':{'staff':69,'money':9002869},
                                  'haungjia':{'landscape':'beatiful','dog':4}
                                  },
                        'hengfeng':{},
                        'yangshang':{},
                        },
            'yingtang':{'yugan':{},
                        'yiangtanshi':{}
                        },
            'ganzhou':{'ei':{},
                       'ei':{}
                       },
            },
      'gx':{'nanning':{},
            'liuzhou':{},
            'guiling':{},
            },
      'hn':{'yueyan':{},
            'hangyang':{},
            'huaihua':{},
                        },
      'gd':{'guangzhou':{},
            'jiangmen':{},
            'shengzheng':{},
            'fosheng':{}
            }}
current_layer=menu
parent_layer=[]
while True:
   for key,value in enumerate(current_layer,1):
       print(key,value)
   choice=input('>>>').strip()
   if len(choice)==0:
     continue
   if choice in current_layer[choice]:
      parent_layer.append(current_layer)
      current_layer=current_layer[choice]
   elif:choice=='b':
     if parent_layer:
        current_layer=parent_layer.pop()
else:
   print('invalid character for your input')
      
   
usage:
 current:at present layer to loop.to implement advanced fuction
         The programe work more concise and clear ,precise