Question: who won this year's women's us open
[{'answer': 'Naomi Osaka', 'provenance': [{'wikipedia_id': '58448505', 'title': "2018 US Open – Women's Singles final", 'start_paragraph_id': 1, 'start_character': 173, 'end_paragraph_id': 1, 'end_character': 184, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '58448505', 'title': "2018 US Open – Women's Singles final", 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 298, 'bleu_score': 0.9632870032952191, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 11907575016700319022}, 'section': 'Section::::Abstract.'}]}]