How many albums did Led Zeppelin release before 1970?
{'directed': True, 'multigraph': False, 'graph': {}, 'nodes': [{'type': 'INTERNAL', 'name_': 'Q633', 'id': 0, 'label': 'Neil Young'}, {'type': 'ANSWER_CANDIDATE_ENTITY', 'name_': 'Q193740', 'id': 1, 'label': 'Live Aid'}, {'type': 'INTERNAL', 'name_': 'Q754841', 'id': 2, 'label': 'Polar Music Prize'}, {'type': 'QUESTIONS_ENTITY', 'name_': 'Q2331', 'id': 3, 'label': 'Led Zeppelin'}, {'type': 'INTERNAL', 'name_': 'Q2808', 'id': 4, 'label': 'Elton John'}, {'type': 'INTERNAL', 'name_': 'Q22343738', 'id': 5, 'label': 'Aubrie Sellers'}], 'links': [{'name_': 'P1344', 'source': 0, 'target': 1, 'label': 'participant in'}, {'name_': 'P1346', 'source': 2, 'target': 3, 'label': 'winner'}, {'name_': 'P1346', 'source': 2, 'target': 4, 'label': 'winner'}, {'name_': 'P1344', 'source': 4, 'target': 1, 'label': 'participant in'}, {'name_': 'P737', 'source': 5, 'target': 0, 'label': 'influenced by'}, {'name_': 'P737', 'source': 5, 'target': 3, 'label': 'influenced by'}]}