Question: who discovered the ancient city of machu pichu
[{'answer': 'Hiram Bingham', 'provenance': [{'wikipedia_id': '80019', 'title': 'Machu Picchu', 'start_paragraph_id': 2, 'start_character': 491, 'end_paragraph_id': 2, 'end_character': 504, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '80019', 'title': 'Machu Picchu', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 550, 'bleu_score': 0.8572468208333881, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8177327223458550236}, 'section': 'Section::::Abstract.'}]}]