Question: when was ain't added to the dictionary
[{'answer': '1961', 'provenance': [{'wikipedia_id': '28723479', 'title': "Ain't", 'start_paragraph_id': 25, 'start_character': 61, 'end_paragraph_id': 25, 'end_character': 65, 'bleu_score': 1.0, 'section': 'Section::::Proscription and stigma.\n'}]}, {'provenance': [{'wikipedia_id': '28723479', 'title': "Ain't", 'start_paragraph_id': 25, 'start_character': 0, 'end_paragraph_id': 25, 'end_character': 553, 'bleu_score': 0.9396430371117861, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 1917474383884753853}, 'section': 'Section::::Proscription and stigma.\n'}]}]