制作随机验证码，不区分大小写

流程：

• 用户执行程序

• 给用户显示需要输入验证码

• 用户输入的值

用户输入的值和显示的值相同时显示正确的信息:否则继续生成验证码等待用户输入

生成随机验证码代码示例：

def check_code():
    import random
    check_code = ''
    for i in range(4):
        current = random.randrange(0,4)
        if current != i:
            temp = chr(random.randint(65,90))
        else:
            temp = random.randint(0,9)
        check_code += str(temp)
    return check_code
code = check_code()
print(code)

def check_code():
    import random
    check_code = ''
    for i in range(4):
        current = random.randrange(0,4)
        if current != i:
            temp = chr(random.randint(65,90))
        else:
            temp = random.randint(0,9)
        check_code += str(temp)
    return check_code
code = check_code()
while True:
    code = check_code()
    print (code)
    v = input('请输入验证码>>>>')
    v1 = v.upper()
    if v1 == code:
        print ('验证码正确')
        break
    else:
        pass