How many number one hits does Rick Astley have?
{'directed': True, 'multigraph': False, 'graph': {}, 'nodes': [{'type': 'QUESTIONS_ENTITY', 'name_': 'Q219237', 'id': 0, 'label': 'Rick Astley'}, {'type': 'INTERNAL', 'name_': 'Q1055036', 'id': 1, 'label': 'Hopelessly'}, {'type': 'ANSWER_CANDIDATE_ENTITY', 'name_': 'Q1319609', 'id': 2, 'label': 'The Ones You Love'}], 'links': [{'name_': 'P175', 'source': 1, 'target': 0, 'label': 'performer'}, {'name_': 'P155', 'source': 1, 'target': 2, 'label': 'follows'}]}