Bill a driving instructor's pupils for a month with block-booking discounts, late-cancellation charges and test fees

# Bill a driving instructor's pupils for November Inputs: `lessons.csv` (each lesson: pupil, date, minutes, status), `pupils.json` (each pupil's `block_booked` flag) and `prices.json` (the hourly rate and the test fee). Every amount is in pounds. Billing rules, per lesson: - Lesson charge = hourly rate x minutes / 60 for each taken lesson (status taken), less 10% for pupils marked block_booked 'yes' in pupils.json. - A late cancellation (status late_cancel) is charged at 50% of the full lesson charge, with no block discount; an early cancellation (status early_cancel) is free. - A test (status test) is charged the flat test_fee, with no discount. - Round each lesson's charge to the cent half-up before adding anything up. Write `out/bills.json`: `{"lessons": {"<pupil>": <sum of taken-lesson charges>, ...}, "late_cancel": {...}, "tests": {...}, "total": {...}, "grand_total": <sum of the totals>}` with every pupil in `pupils.json` in each map (0 where nothing applies). ## How this run works - Work on your own: nobody will answer questions in this task, and writing to `ask/` counts against the run. - Write only under `out/`. Create `out/` if it is missing. Inputs are synthetic; don't fetch anything from the network. - Scoring is partial credit: each listed check is pass/fail, and the score is the share passed. Numbers are compared to within 0.005 unless the task says otherwise.