Python模拟自动存取款机的查询、存取款、修改密码等操作

import msvcrt, sys, os
#定义用星号隐藏密码输入的函数
def psw_input():
  li = []
  while True:
    ch = msvcrt.getch()
    #回车
    if ch == b'\r':
      msvcrt.putch(b'\n')
      break
    #退格
    elif ch == b'\x08':
      if li:
        li.pop()
        msvcrt.putch(b'\b')
        msvcrt.putch(b' ')
        msvcrt.putch(b'\b')
    #Esc
    elif ch == b'\x1b':
      break
    else:
      li.append(ch)
      msvcrt.putch(b'*')
  return li
#定义CSDN银行ATM欢迎界面的函数
def ATM():
  '''
  CSDN银行ATM欢迎界面的函数
  '''
  print("="*14,"Bank of CSDN","="*14,"\n")
  print("{:^42}".format("ATM"),"\n")
  print("="*14,"Bank of CSDN","="*14,"\n")
#CSDN银行用户列表信息，用户信息包含：姓名、余额、密码（6位）、银行卡号（19位）
user_list = [{"name":"张 三","balance":10000,"password":"000000","numbers":"0000000000000000000"},
{"name":"李 四","balance":20000,"password":"111111","numbers":"1111111111111111111"},
{"name":"王 五","balance":30000,"password":"222222","numbers":"2222222222222222222"}]
#定义验证银行卡号与密码匹配的函数
def check(user_name,user_password):
  '''
  验证银行卡号与密码匹配的函数
  ''' 
  for i in range(len(user_list)):
    if user_name == user_list[i]["numbers"] and user_password == user_list[i]["password"]:
      return i #银行卡号与密码匹配则返回该用户在ATM系统内的ID值，否则返回None值
#定义用户登录成功后操作界面的函数
def interface():
  '''
  用户登录成功后操作界面的函数
  '''
  print("="*14,"用户操作界面","="*14,"\n")
  print("{0:2} {1:12} {2:12} {3:12}".format(" ","1. 查询","2. 取款","3. 存款"),"\n")
  print("{0:2} {1:10} {2:12}".format(" ","4. 修改密码","5. 退出"),"\n")
  print("="*42,"\n")
#定义用户查询信息的函数
def inquire(user_id):
  '''
  用户查询信息的函数
  '''
  print("="*14,"账号查询界面","="*14,"\n")
  print("|{0:<4}|{1:<18}|{2:<9}|\n".format("账户名","卡号","余额(RMB)"))
  print("|{0:<5}|{1:<20}|{2:<11}|\n".format(user_list[user_id]["name"],user_list[user_id]["numbers"],user_list[user_id]["balance"]))
#定义用户取款的函数
def withdrawal(amount):
  '''
  用户取款的函数
  '''
  i = user_list[user_id]["balance"]-int(amount)
  if i>=0:
    user_list[user_id]["balance"]-=int(amount)
  else:
    print("账户余额不足\n")
#定义用户存款的函数
def deposit(amount):
  '''
  用户存款的函数
  '''
  user_list[user_id]["balance"]+=int(amount)
#定义用户修改密码的函数
def change_password(old_password,new_password1,new_password2):
  '''
  用户修改密码的函数
  '''
  if old_password == user_list[user_id]["password"]:
    if new_password1 == new_password2:
      user_list[user_id]["password"] = new_password1
      print("新密码修改成功\n")
      return 1
    else:
      print("修改密码失败，您2次输入的新密码不一致\n")
      return 2
  else:
    print("旧密码输入错误\n")
    return 0
#用户登录界面，输入银行卡号和密码
chance = 3 #允许3次用户名或密码输入错误
while True:
  ATM()
  user_name = input("请输入您的银行卡卡号：")
  print("")
  print("请输入您的银行卡密码:", end=' ', flush=True)
  user_password = b''.join(psw_input()).decode()
  print("")
  user_id = check(user_name,user_password)#验证银行卡号与密码是否匹配
  if user_id != None:
    print("登录成功\n")
    while True:
      interface()
      key_word = input("请输入操作选项：")
      print("")
      if key_word == "1":
        inquire(user_id)
        input("按任意键返回上一级目录:")
        print("")
      elif key_word == "2":
        print("="*14,"账号取款界面","="*14,"\n")
        amount = input("请输入取款金额：")
        print("")
        withdrawal(amount)
        inquire(user_id)
        input("按任意键返回上一级目录:")
        print("")
      elif key_word == "3":
        print("="*14,"账号存款界面","="*14,"\n")
        amount = input("请输入存款金额：")
        print("")
        deposit(amount)
        inquire(user_id)
        input("按任意键返回上一级目录:")
        print("")
      elif key_word == "4":
        print("="*14,"密码管理界面","="*14,"\n")
        print("请输入旧密码:", end=' ', flush=True)
        old_password = b''.join(psw_input()).decode()
        print("")
        print("请输入新密码:", end=' ', flush=True)
        new_password1 = b''.join(psw_input()).decode()
        print("")
        print("请再次输入新密码:", end=' ', flush=True)
        new_password2 = b''.join(psw_input()).decode()
        print("")        
        save = change_password(old_password,new_password1,new_password2)
        #如何检测到旧密码输入有误，将直接退出
        if save == 0:
          break
      elif key_word == "5":
        print("="*14,"欢迎下次光临","="*14,"\n")
        break
      else:
        print("="*14,"没有该选项","="*14,"\n")
  else:
    if chance > 1:     
      print("用户名或密码错误，您还有",chance-1,"次机会，请重新输入\n")
      chance -= 1
    else:
      print("对不起，您输入用户名或密码错误已达3次")
      break