What was the second installment of the Mario Brothers games?
{'directed': True, 'multigraph': False, 'graph': {}, 'nodes': [{'type': 'QUESTIONS_ENTITY', 'name_': 'Q37817870', 'id': 0, 'label': 'Mario Bros.'}, {'type': 'ANSWER_CANDIDATE_ENTITY', 'name_': 'Q9884913', 'id': 1, 'label': 'Category:Mario Bros.'}], 'links': [{'name_': 'P910', 'source': 0, 'target': 1, 'label': "topic's main category"}]}