What was the capital of the Achaemenid Empire of Persia?
{'directed': True, 'multigraph': False, 'graph': {}, 'nodes': [{'type': 'INTERNAL', 'name_': 'Q6173448', 'id': 0, 'label': 'Wikipedia:Vital articles/Level/4'}, {'type': 'INTERNAL', 'name_': 'Q48', 'id': 1, 'label': 'Asia'}, {'type': 'QUESTIONS_ENTITY', 'name_': 'Q3746183', 'id': 2, 'label': 'Persis'}, {'type': 'QUESTIONS_ENTITY', 'name_': 'Q389688', 'id': 3, 'label': 'Achaemenid Empire'}, {'type': 'ANSWER_CANDIDATE_ENTITY', 'name_': 'Q35518', 'id': 4, 'label': 'Akkadian'}, {'type': 'INTERNAL', 'name_': 'Q8423', 'id': 5, 'label': 'Cyrus the Great'}], 'links': [{'name_': 'P5008', 'source': 1, 'target': 0, 'label': 'on focus list of Wikimedia project'}, {'name_': 'P30', 'source': 2, 'target': 1, 'label': 'continent'}, {'name_': 'P5008', 'source': 4, 'target': 0, 'label': 'on focus list of Wikimedia project'}, {'name_': 'P5008', 'source': 5, 'target': 0, 'label': 'on focus list of Wikimedia project'}, {'name_': 'P27', 'source': 5, 'target': 3, 'label': 'country of citizenship'}]}