Question: when does halt and catch fire season 4 start
[{'answer': 'August 19 , 2017', 'provenance': [{'wikipedia_id': '31396771', 'title': 'Halt and Catch Fire (TV series)', 'start_paragraph_id': 103, 'start_character': 152, 'end_paragraph_id': 103, 'end_character': 168, 'bleu_score': 1.0, 'section': 'Section::::Reception.:Viewership ratings.\n'}]}]