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