python生成随机验证码

#!/usr/bin/env python
#-*- coding:utf-8 -*-
import random
code = []
for i in range(0,6):
    if i == random.randint(0,6):
        code.append(str(i))
    else:
        M = (random.randint(65,90))
        code.append(str(chr(M)))
print(''.join(code))