[Heidi] received a very nice letter from her grandfather [Clarence]. [Heidi] and her sister [Linda] played golf together. [Heidi] won easily.
('Linda', 'Clarence')
[Heidi] and her sister [Linda] played golf together. [Heidi] won easily. [Heidi] received a very nice letter from her grandfather [Clarence].
[{('Linda', 'grandfather', 'Clarence'): [('Linda', 'sister', 'Heidi'), ('Heidi', 'grandfather', 'Clarence')]}]
['sister', 'grandfather']