Python如何实现时间累加的计算器

import datetime
 
 
def time_split(t):
    t = str(t).split(":")
    if len(t) == 2:
        t_h = 0
        t_m = t[0]
        t_s = t[1]
    if len(t) == 3:
        t_h = t[0]
        t_m = t[1]
        t_s = t[2]
    return t_h, t_m, t_s
 
 
def time_add(t1, t2):
    t1_h = time_split(t1)[0]
    t1_m = time_split(t1)[1]
    t1_s = time_split(t1)[2]
    t2_h = time_split(t2)[0]
    t2_m = time_split(t2)[1]
    t2_s = time_split(t2)[2]
    t3_s = int(t1_s) + int(t2_s)
    t3_sup = 0
    while t3_s >= 60:
        t3_sup += 1
        t3_s = int(t3_s) - 60
    t3_m = int(t1_m) + int(t2_m) + int(t3_sup)
    t3_mup = 0
    while t3_m >= 60:
       t3_mup += 1
       t3_m = int(t3_m) - 60
    t3_h = int(t1_h) + int(t2_h) + int(t3_mup)
    t3 = str(t3_h).zfill(2) + ":" + str(t3_m).zfill(2) + ":" + str(t3_s).zfill(2)
    return t3
 
 
if __name__ == "__main__":
    flag = True
    index = 0
    print(u"欢迎使用时间相加计算!")
    print(u"请注意您的时间格式,且确保你的输入法是英文输入 ==> 时:分:秒 ==> 00:00:00")
    print(u"将会在同级目录下生产log.txt文件来记录你的输入")
    print(u"中文输入将会导致程序闪退!!!")
    while flag:
        time_in = input(u"请输入你要计算的时间(请确保你的“:”是英文字符!!!,输入“#”结束):")
        with open('log.txt', mode='a') as filename:
            filename.write(str(datetime.datetime.now()))
            filename.write(u"请输入你要计算的时间(请确保你的“:”是英文字符!!!,输入“#”结束):" + time_in + u"\n")
            filename.close()
        if time_in == "#":
            flag = False
            print(u"计算结束,结果为:", time_last)
            with open('log.txt', mode='a') as filename:
                filename.write(str(datetime.datetime.now()))
                filename.write(u"计算结束,结果为:" + time_last + u"\n")
                filename.close()
            break
        if index == 0:
            time_last = time_add(time_in, "00:00:00")
        else:
            time_last = time_add(time_in, time_last)
        print("第", index+1 , "次合计:", time_last)
        with open('log.txt', mode='a') as filename:
            filename.write(str(datetime.datetime.now()))
            filename.write(u"第" + str(index+1) + u"次合计:" + time_last + u"\n")
            filename.close()
        index += 1