Question: who performed the first successful open heart surgery
[{'answer': 'Daniel Hale Williams', 'provenance': [{'wikipedia_id': '1515846', 'title': 'Daniel Hale Williams', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 20, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '1515846', 'title': 'Daniel Hale Williams', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 368, 'bleu_score': 0.831298505224899, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 2243846410104250468}, 'section': 'Section::::Abstract.'}]}]