Question: when was happy days are here again written
[{'answer': '1929', 'provenance': [{'wikipedia_id': '3837259', 'title': 'Happy Days Are Here Again', 'start_paragraph_id': 1, 'start_character': 53, 'end_paragraph_id': 1, 'end_character': 57, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '3837259', 'title': 'Happy Days Are Here Again', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 746, 'bleu_score': 0.8640213888958461, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 2126533426029000814}, 'section': 'Section::::Abstract.'}]}]