[Jacob] asked his father [Wayne] if they could go to the library. [Wayne]'s father [Clarence] was there already, waiting for them.
('Jacob', 'Clarence')
[Jacob] asked his father [Wayne] if they could go to the library. [Wayne]'s father [Clarence] was there already, waiting for them.
[{('Jacob', 'grandfather', 'Clarence'): [('Jacob', 'father', 'Wayne'), ('Wayne', 'father', 'Clarence')]}]
['father', 'father']