exercise6/answer.py: chained comparisons like 70 <= score < 90 — long form or idiomatic form?

[dab00gieman]

The grading chains in answers/exercise6/answer.py spell out bounds as:

score < 90 and score >= 70

Python's idiomatic chained comparison is 70 <= score < 90, which the same file's neighbours could use throughout. For a beginner-focused curriculum, is the long form deliberate (making both bounds explicit for learners), or worth a follow-up exercise on chained comparisons as the canonical rewrite?