利用一个random模块生成一个随机验证码功能

import random
checkcode = ''
for i in range(4):
    current = random.randrange(0,4)
    if current == i:
        tmp = chr(random.randint(65,90))
    else:
        tmp = random.randint(0,9)
    checkcode+=str(tmp)
print(checkcode)