python随机生成包含字母数字的六位验证码

#python随机生成包含字母数字的六位验证码
import random

def v_code():
    ret = ""
    for i in range(6):
        num = random.randint(0, 9)
        # num = chr(random.randint(48,57))#ASCII表示数字
        letter = chr(random.randint(97, 122))#取小写字母
        Letter = chr(random.randint(65, 90))#取大写字母
        s = str(random.choice([num,letter,Letter]))
        ret += s
    return ret
print(v_code())