Question: who won this year's us open golf
[{'answer': 'Brooks Koepka', 'provenance': [{'wikipedia_id': '50875497', 'title': '2017 U.S. Open (golf)', 'start_paragraph_id': 1, 'start_character': 131, 'end_paragraph_id': 1, 'end_character': 144, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]