{"task":"The receipt printer retried. Keep one row per book_copy, even when receipt_id differs.","node_hint":"Use Remove Duplicates. Compare selected field book_copy.","rows":[{"receipt_id":"LIB-P1","book_copy":"COPY-42","desk":"east"},{"receipt_id":"LIB-P2","book_copy":"COPY-17","desk":"west"},{"receipt_id":"LIB-P3","book_copy":"COPY-42","desk":"east"},{"receipt_id":"LIB-P4","book_copy":"COPY-65","desk":"east"},{"receipt_id":"LIB-P5","book_copy":"COPY-17","desk":"west"},{"receipt_id":"LIB-P6","book_copy":"COPY-83","desk":"west"}],"check_yourself":{"distinct_book_copies":4,"book_copies":["COPY-17","COPY-42","COPY-65","COPY-83"]},"practice":true,"lesson":"dedupe"}