[Lillian] and her brother [Nicholas] watched TV together. [Dale] was invited to watch too, because [Lillian] is his sister.
('Dale', 'Nicholas')
[Lillian] and her brother [Nicholas] watched TV together. [Dale] was invited to watch too, because [Lillian] is his sister.
[{('Dale', 'brother', 'Nicholas'): [('Dale', 'sister', 'Lillian'), ('Lillian', 'brother', 'Nicholas')]}]
['sister', 'brother']