[Theresa] asked her two sisters [Nancy] and [Amy] if they were free for coffee this coming weekend.
('Amy', 'Nancy')
[Theresa] asked her two sisters [Nancy] and [Amy] if they were free for coffee this coming weekend.
[{('Amy', 'sister', 'Nancy'): [('Amy', 'sister', 'Theresa'), ('Theresa', 'sister', 'Nancy')]}]
['sister', 'sister']