How many books are in the Hobbit series?
{'directed': True, 'multigraph': False, 'graph': {}, 'nodes': [{'type': 'QUESTIONS_ENTITY', 'name_': 'Q74287', 'id': 0, 'label': 'The Hobbit'}, {'type': 'INTERNAL', 'name_': 'Q892', 'id': 1, 'label': 'J. R. R. Tolkien'}, {'type': 'INTERNAL', 'name_': 'Q378913', 'id': 2, 'label': 'The Lord of the Rings'}, {'type': 'ANSWER_CANDIDATE_ENTITY', 'name_': 'Q74229', 'id': 3, 'label': 'Hobbit'}], 'links': [{'name_': 'P800', 'source': 1, 'target': 0, 'label': 'notable work'}, {'name_': 'P58', 'source': 2, 'target': 1, 'label': 'screenwriter'}, {'name_': 'P155', 'source': 2, 'target': 3, 'label': 'follows'}]}