Question: how many books are in the narnia series
[{'answer': 'seven', 'provenance': [{'wikipedia_id': '30685', 'title': 'The Chronicles of Narnia', 'start_paragraph_id': 1, 'start_character': 40, 'end_paragraph_id': 1, 'end_character': 45, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '30685', 'title': 'The Chronicles of Narnia', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 460, 'bleu_score': 0.5175164790936471, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8129802252093928875}, 'section': 'Section::::Abstract.'}]}]