python写的随机生成身份证号码的函数

= len(x1)
    if xlen != 18 and xlen != 15:
        return u'身份证号码长度错误'

    try:
        if xlen == 18:
            x2 = x1[6:14]
            x3 = time.strptime(x2, '%Y%m%d')
            if x2 < '19000101' or x3 > time.localtime():
                return u'时间错误，超过允许的时间范围'
        else:
            x2