[Nicholas] and his sister [Nancy] went to the ice skating rink. [Nicholas] fell down and [Nancy] laughed at him. [Nancy] was mad at her brother [Dale], because [Dale] had called her fat.
('Nicholas', 'Dale')
[Nicholas] and his sister [Nancy] went to the ice skating rink. [Nicholas] fell down and [Nancy] laughed at him. [Nancy] was mad at her brother [Dale], because [Dale] had called her fat.
[{('Nicholas', 'brother', 'Dale'): [('Nicholas', 'sister', 'Nancy'), ('Nancy', 'brother', 'Dale')]}]
['sister', 'brother']