Who was famed author Mary Shelley's husband?
{'directed': True, 'multigraph': False, 'graph': {}, 'nodes': [{'type': 'ANSWER_CANDIDATE_ENTITY', 'name_': 'Q51955019', 'id': 0, 'label': 'BEIC Digital Library'}, {'type': 'INTERNAL', 'name_': 'Q692', 'id': 1, 'label': 'William Shakespeare'}, {'type': 'INTERNAL', 'name_': 'Q40640', 'id': 2, 'label': 'Ray Bradbury'}, {'type': 'QUESTIONS_ENTITY', 'name_': 'Q47152', 'id': 3, 'label': 'Mary Shelley'}], 'links': [{'name_': 'P1343', 'source': 1, 'target': 0, 'label': 'described by source'}, {'name_': 'P737', 'source': 2, 'target': 1, 'label': 'influenced by'}, {'name_': 'P737', 'source': 2, 'target': 3, 'label': 'influenced by'}]}