Question: when does the season finale of game of thrones air
[{'answer': 'August 27 , 2017', 'provenance': [{'wikipedia_id': '47398513', 'title': 'Game of Thrones (season 7)', 'start_paragraph_id': 1, 'start_character': 144, 'end_paragraph_id': 1, 'end_character': 160, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]