Question: where is the world series of poker main event held
[{'answer': 'Las Vegas', 'provenance': [{'wikipedia_id': '33116', 'title': 'World Series of Poker', 'start_paragraph_id': 1, 'start_character': 83, 'end_paragraph_id': 1, 'end_character': 92, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '33116', 'title': 'World Series of Poker', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 441, 'bleu_score': 0.9408228243926111, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16558576159056066735}, 'section': 'Section::::Abstract.'}]}]