Who was the Roman emperor in the West overthrown by?
{'directed': True, 'multigraph': False, 'graph': {}, 'nodes': [{'type': 'QUESTIONS_ENTITY', 'name_': 'Q1747689', 'id': 0, 'label': 'Ancient Rome'}, {'type': 'INTERNAL', 'name_': 'Q2277', 'id': 1, 'label': 'Roman Empire'}, {'type': 'QUESTIONS_ENTITY', 'name_': 'Q42834', 'id': 2, 'label': 'Western Roman Empire'}, {'type': 'ANSWER_CANDIDATE_ENTITY', 'name_': 'Q115738657', 'id': 3, 'label': 'Ravenna'}], 'links': [{'name_': 'P361', 'source': 1, 'target': 0, 'label': 'part of'}, {'name_': 'P1366', 'source': 1, 'target': 2, 'label': 'replaced by'}, {'name_': 'P1365', 'source': 2, 'target': 1, 'label': 'replaces'}, {'name_': 'P17', 'source': 2, 'target': 2, 'label': 'country'}, {'name_': 'P36', 'source': 2, 'target': 3, 'label': 'capital'}]}