Add Inline Comments

Add helpful comments to this code:

CODE:
[Paste your code]

Comment style: [language conventions]

Add comments for:
- [ ] Function/method purpose (docstrings)
- [ ] Complex logic explanation
- [ ] Non-obvious decisions (why, not what)
- [ ] TODO/FIXME where appropriate

DON'T add comments that just restate what the code does.
DO explain WHY for anything non-obvious.