[Nicholas] went skiing with his brother [Dale]. [Dale]'s sister [Lillian] watched from the ski lodge.
('Lillian', 'Nicholas')
[Nicholas] went skiing with his brother [Dale]. [Dale]'s sister [Lillian] watched from the ski lodge.
[{('Lillian', 'brother', 'Nicholas'): [('Lillian', 'brother', 'Dale'), ('Dale', 'brother', 'Nicholas')]}]
['brother', 'brother']