Question: who sang i left my heart in san francisco
[{'answer': 'Tony Bennett', 'provenance': [{'wikipedia_id': '1872941', 'title': 'I Left My Heart in San Francisco', 'start_paragraph_id': 1, 'start_character': 212, 'end_paragraph_id': 1, 'end_character': 224, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '1872941', 'title': 'I Left My Heart in San Francisco', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 224, 'bleu_score': 0.8723360571509821, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17112980009255902607}, 'section': 'Section::::Abstract.'}]}]