火车票身份证号的打码真不靠谱！

今天坐火车，发现火车票上的身份证号仅仅把出生月日这四位打了码，满打满算不超过 400 种可能性。
另外，最后一位校验码也没有打码，感觉又可以排除不少。

回来简单写了个脚本，验证了一下。发现加上校验码，最终只有不超过 40 种可能性（试了好几个身份证号）。
这码打的，跟没打差不多了。

附上代码：

#!/usr/bin/env python3
# -*- encoding: utf-8 -*-

def ID_number_check(num_in):
    if len(num_in) != 18:
        return False
    try:
        int(num_in[:17])
    except:
        return False
    check_num=num_in[-1]
    total_sum=int(num_in[0])*7+int(num_in[1])*9+int(num_in[2])*10+int(num_in[3])*5+int(num_in[4])*8+int(num_in[5])*4+int(num_in[6])*2+int(num_in[7])*1+int(num_in[8])*6+int(num_in[9])*3+int(num_in[10])*7+int(num_in[11])*9+int(num_in[12])*10+int(num_in[13])*5+int(num_in[14])*8+int(num_in[15])*4+int(num_in[16])*2
    remain=total_sum%11
    if remain == 0:
        check=1
    elif remain == 1:
        check=0
    elif remain == 2:
        check='X'
    elif remain == 3:
        check=9
    elif remain == 4:
        check=8
    elif remain == 5:
        check=7
    elif remain == 6:
        check=6
    elif remain == 7:
        check=5
    elif remain == 8:
        check=4
    elif remain == 9:
        check=3
    elif remain == 10:
        check=2
    if str(check_num) == str(check):
        return True
    else:
        return False

def ID_number_guess(num_in):
    num_in=num_in.upper()
    if len(num_in) != 18:
        print('请输入 18 位身份证号')
        exit(1)
    part1=num_in[:10]
    part2=num_in[-4:]
    year=num_in[6:10]
    Mons=range(1, 13)
    for Mon in Mons:
        if Mon in [1, 3, 5, 7, 8, 10, 12]:
            Days=range(1, 32)
        elif Mon == 2 and leap_year_check(year):
            Days=range(1, 30)
        elif Mon == 2 and not leap_year_check(year):
            Days=range(1, 29)
        else:
            Days=range(1, 31)
        if len(str(Mon)) == 1:
            Mon='0' +str(Mon)
        for Day in Days:
            if len(str(Day)) == 1:
                Day='0' +str(Day)
            num_out=part1 +str(Mon) +str(Day) +part2
            if ID_number_check(num_out):
                print(num_out)

def leap_year_check(year):
    try:
        year=int(year)
    except:
        return False
    if year % 400 == 0:
        return True
    elif year % 100 != 0 and year % 4 == 0:
        return True
    else:
        return False

if __name__ == '__main__':
    ID_number=input('请输入要猜测的身份证号: ')
    ID_number_guess(ID_number)