python简单实现随机验证码

这是自己在学习pyton时写的一个随机验证码,有不对的地方欢迎指出

代码

import random

def verification():

    lis = ''

    for i in range(4):

        Suiji = random.randint(1,3)

        if Suiji == 1:

            ra = random.randint(97,122)

            yzm = chr(ra)

            lis += yzm

        elif Suiji == 2:

            ra = random.randint(65, 90)

            yzm = chr(ra)

            lis += yzm

        else:

            ra = random.randint(0,9)

            yzm = ra

            lis += str(yzm)

    return lis

Yanzhengma = verification()

print(Yanzhengma)