How to move optparse from main to function?

[Jason Drew]

You're welcome!

As usual, each of us is free to write the code whichever way works best
for the particular problem at hand. That's why the module documentation
often avoids advocating here-is-the-one-best-way-to-do-it.  I just like
sticking all the option setup stuff in a single function because it's
conceptually all the same and it makes the main() function or whatever
read shorter. It's partly down to experience, what little of it I can
claim.

Good luck!