How many books are in the Scary Stories to Tell in the Dark series?
{'directed': True, 'multigraph': False, 'graph': {}, 'nodes': [{'type': 'QUESTIONS_ENTITY', 'name_': 'Q7430560', 'id': 0, 'label': 'Scary Stories to Tell in the Dark'}, {'type': 'ANSWER_CANDIDATE_ENTITY', 'name_': 'Q56274092', 'id': 1, 'label': 'Scary Stories to Tell in the Dark'}], 'links': [{'name_': 'P4969', 'source': 0, 'target': 1, 'label': 'derivative work'}, {'name_': 'P144', 'source': 1, 'target': 0, 'label': 'based on'}]}