[Heidi] and her brother [Robert] went to the basketball game and had a great time. [Louise] and her sister [Heidi] played golf together. [Louise] won easily.
('Robert', 'Louise')
[Heidi] and her brother [Robert] went to the basketball game and had a great time. [Louise] and her sister [Heidi] played golf together. [Louise] won easily.
[{('Robert', 'sister', 'Louise'): [('Robert', 'sister', 'Heidi'), ('Heidi', 'sister', 'Louise')]}]
['sister', 'sister']