Question: who sang the ballad of john and yoko
[{'answer': 'the Beatles', 'provenance': [{'wikipedia_id': '1885347', 'title': 'The Ballad of John and Yoko', 'start_paragraph_id': 1, 'start_character': 132, 'end_paragraph_id': 1, 'end_character': 143, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '1885347', 'title': 'The Ballad of John and Yoko', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 301, 'bleu_score': 0.7564809207900101, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17865106934613020076}, 'section': 'Section::::Abstract.'}]}]