[Lillian] took her son [Douglas] to the football game. [Nicholas] did n't get along very well with his sister [Lillian] for some reason.
('Nicholas', 'Douglas')
[Nicholas] did n't get along very well with his sister [Lillian] for some reason. [Lillian] took her son [Douglas] to the football game.
[{('Nicholas', 'nephew', 'Douglas'): [('Nicholas', 'sister', 'Lillian'), ('Lillian', 'son', 'Douglas')]}]
['sister', 'son']