Python Shopping cart feature implementation

name =  "Gaowang" pwd =  "123.ABC" list_he=[]            #定义空列表, after receiving For i in range (3):     username = input (" Please enter your account number: ")     password = input (" Please enter your password: ")     if  username == name and password == pwd:  #判断帐号与密码是否符合             print ("Congratulations,%s, login successful, welcome"  % username)          offer = int (Input ("Enter your stored value card amount:"))          print ("        ------------------------------------         --         Welcome to the shopping mall           --         ------ ------------------------------                      ")          #格式化输出          print ("        1: Get Product List       &NBSP;&NBSP;&NBSP;2: Recharge Your Shopping card         3: Exit system           ")            #格式化输出          gong_neng = int (Input ("Please select your feature"))          if gong_neng == 1:  #  Enter the purchase goods link              while True:                 shipin2 = [[' milk ',  20], [' jerky ',  30], [' Rice ',  15], [' bread ', 15], [' beer ', 3.5]]                 for i, a in enumerate (shipin2, 1):    #循环打印商品列表                       print ("Ordinal:%s"  % i,  "Product:%s"  % a[0],  "Price:%s Yuan"  % a[1])                  huo_qu = int ( Input ("Please enter the item you want to buy, enter [0] exit"))                  if huo_qu > 0 and huo_qu <= len (shipin2):       #验证输入是否正确                          j=shipin2[huo_qu-1]  #购买的商品和价格       &nBsp;                 if  j[1]>offer :          #判断想要购买的商品价格是否超过了余额                               print ("Your balance is insufficient, please recharge in time")                           else:                             offer = offer - j[ 1]     #算出购买商品后的价格                              print ("The item you purchased is %s " % j[0], " remainingAmount is%s " % offer)      #输出购买的商品                               list_he.append (j[0])       #把已购买商品添加至集合中                               print ("You have purchased%s"%list_he)         #已购买商品集合                 elif huo_ qu==0:                     print ("Exit program, Goodbye")                      for m in list_he :                          print ("You have purchased%s"%m)                       break                 else:                     print ("Mall cargo temporarily short, please enter the correct product serial number")         elif gong_ neng == 2:  #  Prepaid Shopping Card function              chongzhi=int (Input ("Please enter the amount you want to recharge"))              if chongzhi>0:                 offer+=chongzhi                 print ("RechargeSuccessful, current balance is%s "%offer)              else:                 print ("Reload failed")                  break         elif gong_neng==3:  #  Exit System              print ("Exit system success")          break    else:        print ("The account or password is not entered correctly, Please re-enter ") Else:    print (" Try to run the program again if the user name or password exceeds the maximum number of times ")

Python Shopping cart feature implementation