Question: how many episodes are in season 4 of switched at birth
[{'answer': '20', 'provenance': [{'wikipedia_id': '43558348', 'title': 'Switched at Birth (season 4)', 'start_paragraph_id': 1, 'start_character': 14, 'end_paragraph_id': 1, 'end_character': 16, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]