We would have to see the actual parse_args function to give you a good answer. All of the scripts we run against our huge datasets have a common include shell script, i.e., another small script is sourced. Keeps our common modules easy to maintain - just look in only one place.

The argument parsing it does loops over available arguments. If none are present there are a few default values used. So it does not "care" if there are arguments or not.

So. This is what someone else does. What your script does, I do not know for sure.