Remove html tag (e.g.. color hex code) from SubRip (.srt) subtitle file

clean_srt_file.py

#!/usr/bin/env python3

import re
import sys
import os

def show_help():
    print("Usage:")
    print(sys.argv[0] + " <input_srt_file>" + " <output_srt_file>")


if len(sys.argv) > 3:
    show_help()
    sys.exit()
elif len(sys.argv) == 3:
    unclean_file = sys.argv[1]
    cleaned_file = sys.argv[2]
else:
    unclean_file = sys.argv[1]
    cleaned_file = False

pattern = r"<(.|\n)*?>"

try:
    with open(unclean_file, 'r') as f:
        sub_txt = f.read()

        cleaned = re.search(pattern, sub_txt)

        if not cleaned:
            print("{} is cleaned".format(unclean_file))
            sys.exit()
        else:
            clean_sub_txt = re.sub(pattern, "", sub_txt)

        if(cleaned_file):
            try:
                with open(cleaned_file, 'w') as w:
                    w.write(clean_sub_txt)
            except PermissionError:
                print("ERROR: Can not write file {}".format(cleaned_file))
        else:
            print(clean_sub_txt)

except FileNotFoundError:
    print("ERROR: Subtitle file not found")