Question: when did season 4 of gotham come out
[{'answer': 'September 21 , 2017', 'provenance': [{'wikipedia_id': '54664625', 'title': 'Gotham (season 4)', 'start_paragraph_id': 80, 'start_character': 155, 'end_paragraph_id': 80, 'end_character': 176, 'bleu_score': 1.0, 'section': 'Section::::Release.:Broadcast.\n'}]}, {'provenance': [{'wikipedia_id': '54664625', 'title': 'Gotham (season 4)', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 431, 'bleu_score': 0.970362113628587, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 11931924260431892878}, 'section': 'Section::::Abstract.'}]}]