Question: how many episodes are there in marcella series 2
[{'answer': '8', 'provenance': [{'wikipedia_id': '49986182', 'title': 'Marcella (TV series)', 'start_paragraph_id': 4, 'start_character': 123, 'end_paragraph_id': 4, 'end_character': 124, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]