[George] liked to talk about his sister, [Nancy]. [Amy] and her sister [Nancy] played golf together. [Amy] won easily.
('George', 'Amy')
[George] liked to talk about his sister, [Nancy]. [Amy] and her sister [Nancy] played golf together. [Amy] won easily.
[{('George', 'sister', 'Amy'): [('George', 'sister', 'Nancy'), ('Nancy', 'sister', 'Amy')]}]
['sister', 'sister']