Question: when was the first triple bypass surgery performed
[{'answer': 'May 2 , 1960'}, {'provenance': [{'wikipedia_id': '195248', 'title': 'Coronary artery bypass surgery', 'start_paragraph_id': 96, 'start_character': 0, 'end_paragraph_id': 96, 'end_character': 856, 'bleu_score': 0.9854535765681661, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16137398674533366092}, 'section': 'Section::::History.\n'}]}]