[Robert]'s father [Wayne] and grandfather [Clarence] went to the park to play chess.
('Wayne', 'Clarence')
[Robert]'s father [Wayne] and grandfather [Clarence] went to the park to play chess.
[{('Wayne', 'father', 'Clarence'): [('Wayne', 'son', 'Robert'), ('Robert', 'grandfather', 'Clarence')]}]
['son', 'grandfather']