Checkpoint
One last thing before we move on. Same surface as a write step — but the lesson doesn't complete until this passes.
The mission, miniature: write ingest(start_page) that pages until empty, validates each record (float-parseable amt), upserts clean rows into the dataset dict keyed by id, and adds bad record ids to the quarantine SET. Run it twice (a full resume) and prove nothing duplicated: dataset=2, quarantine=1, pages=2, ids [1, 3].