Who is the most followed musician on YouTube?
{'directed': True, 'multigraph': False, 'graph': {}, 'nodes': [{'type': 'QUESTIONS_ENTITY', 'name_': 'Q866', 'id': 0, 'label': 'YouTube'}, {'type': 'ANSWER_CANDIDATE_ENTITY', 'name_': 'Q27863097', 'id': 1, 'label': '3GPP file format'}, {'type': 'INTERNAL', 'name_': 'Q51883041', 'id': 2, 'label': 'YouTube Space Rio'}], 'links': [{'name_': 'P4290', 'source': 2, 'target': 0, 'label': 'official app'}, {'name_': 'P1072', 'source': 2, 'target': 1, 'label': 'readable file format'}]}