Question: how many episodes in the unforgotten season 2
[{'answer': '6', 'provenance': [{'wikipedia_id': '48137666', 'title': 'Unforgotten', 'start_paragraph_id': 3, 'start_character': 79, 'end_paragraph_id': 3, 'end_character': 80, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]