Question: who won the 7 man elimination chamber match
[{'answer': 'Roman Reigns', 'provenance': [{'wikipedia_id': '55948000', 'title': 'Elimination Chamber (2018)', 'start_paragraph_id': 2, 'start_character': 91, 'end_paragraph_id': 2, 'end_character': 103, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '55948000', 'title': 'Elimination Chamber (2018)', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 777, 'bleu_score': 0.964583525681703, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 13759992505926645407}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '55948000', 'title': 'Elimination Chamber (2018)', 'section': 'Section::::Abstract.', 'start_paragraph_id': 2, 'end_paragraph_id': 2, 'meta': {'evidence_span': [', Roman Reigns won the first-ever seven-man Elimination Chamber match to become the number one contender against Brock Lesnar for the Universal Championship at WrestleMania 34.', 'Roman Reigns won the first-ever seven-man Elimination Chamber match', 'Six matches were contested at the event, including one on the pre-show. In the main event, Roman Reigns won the first-ever seven-man Elimination Chamber match to become the number one contender against Brock Lesnar for the Universal Championship at WrestleMania 34']}}]}]