Exercise 3: Two Fixes for the Stale Comment — Possible Solution
====================================================================

FIX 1: UPDATE THE COMMENT TO MATCH THE CODE
------------------------------
    def calculate_total(items):
        # returns the sum of item prices, discounted by the loyalty program
        total = sum(item['price'] for item in items)
        total = total * 0.9
        return total

FIX 2: RENAME THE FUNCTION, DROP THE COMMENT
------------------------------
    def calculate_discounted_total(items):
        total = sum(item['price'] for item in items)
        total = total * 0.9
        return total

BOTH FIXES VERIFIED CORRECT AND EQUIVALENT
------------------------------
    fix 1 (updated comment) result: 135.0 - comment now accurately says discounted
    fix 2 (renamed function) result: 135.0 - name itself says discounted
    both fixes produce the same correct behavior: True

Both fixes correctly compute 135.0 for the same $150 order, and both
now accurately describe what the function does - fix 1 via a corrected
comment, fix 2 via a name that states the behavior directly.

WHICH FIX SURVIVES A SECOND, FUTURE CHANGE BETTER
------------------------------
Fix 1 relies on a human remembering to update the comment a SECOND
time if the function changes again - for example, if the discount rate
later becomes tiered by customer type. Nothing about fix 1's own
structure makes that more likely to happen than the original failure
this chapter already verified (a real 10% discount added with the
comment never updated). The comment's own accuracy depends entirely on
discipline that has already been shown, in this exact function, to
fail once.

Fix 2's own name, calculate_discounted_total, would need to be
EDITED (not just remembered) if the function stopped applying any
discount at all - but as long as it keeps computing SOME kind of
discounted total, the name stays accurate regardless of how the
discount itself changes (a different rate, a tiered rate, a seasonal
rate) - because "discounted total" is a description broad enough to
remain true across many actual implementations, without needing a
separate maintenance step every time the specific number changes.

WHY THIS WORKS AS AN ANSWER
------------------------------
Both fixes are implemented and verified to produce identical, correct
results, and the comparison of which one survives a future change
better is grounded in a genuine structural difference (a name only
needs updating when its own broad claim becomes false, while a comment
needs updating every time ANY detail it describes changes) rather than
a general preference for one style over the other.