Question: when were the first thermos flasks produced for commercial use
[{'answer': '1904', 'provenance': [{'wikipedia_id': '30272734', 'title': 'Thermos L.L.C.', 'start_paragraph_id': 1, 'start_character': 151, 'end_paragraph_id': 1, 'end_character': 155, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]