Refactor safely

Change the shape, not the behavior.

Steps

1. Make sure a test captures the current behavior first (add a characterization test if needed).
2. Name the smell: long function, duplication, unclear names, deep nesting, mixed concerns.
3. Refactor in small, reversible steps — rename, extract, inline — running tests after each.
4. Keep the public API stable unless the task explicitly allows changing it.
5. Stop when it's clear enough; resist gold-plating.

Output

The refactored code, plus a short list of the moves you made and why behavior is preserved.