Question: who won the rugby 7 in las vegas
[{'answer': 'the United States', 'provenance': [{'wikipedia_id': '56361805', 'title': '2018 USA Sevens', 'start_paragraph_id': 2, 'start_character': 26, 'end_paragraph_id': 2, 'end_character': 43, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '56361805', 'title': '2018 USA Sevens', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 217, 'bleu_score': 0.869296000773157, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 12746205872190337078}, 'section': 'Section::::Abstract.'}]}]