fix py script bug

import sys

filename = "sustechthesis.dtx"

new_version = "1.3.7"

new_date = "2021/11/02"

def change_meta(version, date):

    with open(filename, "r", encoding="utf-8") as f1:

        with open("{filename}.bak", "w", encoding="utf-8") as f2:

        with open(f"{filename}.bak", "w", encoding="utf-8") as f2:

            for line in f1:

                if "Southern University of Science and Technology Thesis Template" in line:

                    print(line)

                    line = re.sub("\d\.\d\.\d", version, line)

                    line = re.sub("\d+\.\d+\.\d+", version, line)

                    line = re.sub("\d{4}/\d{2}/\d{2}", date, line)

                    f2.write(line)

                    print(line)

                elif "\\def\\version" in line:

                    print(line)

                    line = re.sub("\d\.\d\.\d", version, line)

                    line = re.sub("\d+\.\d+\.\d+", version, line)

                    f2.write(line)

                    print(line)

                else:

                    f2.write(line)

    os.remove(filename)

            os.rename("{filename}.bak", filename)

    os.rename(f"{filename}.bak", filename)

def get_meta():

    with open(filename, "r", encoding="utf-8") as f1:

        for line in f1:

            if "Southern University of Science and Technology Thesis Template" in line:

                try:

                    version = re.findall("(\d+)\.(\d+)\.(\d+)", line)[0]

                    date = re.findall("\d{4}/\d{2}/\d{2}", line)

                    return {

                        "ver": version,

                        "date": date

                    }

                except:

                    return None

def bump_version(version, delta=1, pos=-1):

    a, b, c = version

    ver = [int(a), int(b), int(c)]

    ver[pos] = delta+ver[pos]

    ver_str = [str(i) for i in ver]

    return ".".join(ver_str)

if __name__ == "__main__":

    import argparse

    import time

    try:

        new_version = bump_version(get_meta()["ver"])

    except:

        new_version = "0.0.1"

    now_date = time.strftime("%Y/%m/%d", time.localtime())

    parser = argparse.ArgumentParser()

    parser.add_argument("--version", "-v", default=new_version,

                        help='release version')

    parser.add_argument("--date", "-d", default=new_date,

    parser.add_argument("--date", "-d", default=now_date,

                        help='release date')

    parser.add_argument("--dev", action='store_true',

                        help='change the meta-data for develop build')

    args = parser.parse_args()

    if args.dev:

        now_date = time.strftime("%Y/%m/%d", time.localtime())

        dev_version = "DEV.BUILD"

        try:

            git_head_sha = os.popen(r"git log -1 --format='%H'").readlines()[0]