Question: how many episodes in praky blinders season 4
[{'answer': '6', 'provenance': [{'wikipedia_id': '38432808', 'title': 'Peaky Blinders (TV series)', 'start_paragraph_id': 3, 'start_character': 167, 'end_paragraph_id': 3, 'end_character': 168, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]