Question: how many seasons of once upon a time is there
[{'answer': '7', 'provenance': [{'wikipedia_id': '4704229', 'title': 'Once Upon a Time (TV series)', 'start_paragraph_id': 16, 'start_character': 38, 'end_paragraph_id': 16, 'end_character': 39, 'bleu_score': 1.0, 'section': 'Section::::Series overview.:Season 5 (2015–16).\n'}]}]