Question: when did the sands hotel in las vegas close
[{'answer': 'June 30 , 1996', 'provenance': [{'wikipedia_id': '1460540', 'title': 'Sands Hotel and Casino', 'start_paragraph_id': 21, 'start_character': 533, 'end_paragraph_id': 21, 'end_character': 547, 'bleu_score': 1.0, 'section': 'Section::::History.:Later history.\n'}]}]