Question: when was the song old macdonald had a farm written
[{'answer': '1917', 'provenance': [{'wikipedia_id': '3188760', 'title': 'Old MacDonald Had a Farm', 'start_paragraph_id': 3, 'start_character': 7, 'end_paragraph_id': 3, 'end_character': 11, 'bleu_score': 1.0, 'section': 'Section::::Early versions.\n'}]}]