Question: when did they film season 2 of stranger things
[{'answer': '2016', 'provenance': [{'wikipedia_id': '46301800', 'title': 'Stranger Things', 'start_paragraph_id': 4, 'start_character': 68, 'end_paragraph_id': 4, 'end_character': 72, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]