[Nancy] and [Lillian] are sisters who have one brother named [Dale].
('Lillian', 'Nancy')
[Nancy] and [Lillian] are sisters who have one brother named [Dale].
[{('Lillian', 'sister', 'Nancy'): [('Lillian', 'brother', 'Dale'), ('Dale', 'sister', 'Nancy')]}]
['brother', 'sister']