[Robert] went to the park with his father, [Wayne]. [Robert] was going to celebrate Christmas with his grandfather [Clarence].
('Wayne', 'Clarence')
[Robert] went to the park with his father, [Wayne]. [Robert] was going to celebrate Christmas with his grandfather [Clarence].
[{('Wayne', 'father', 'Clarence'): [('Wayne', 'son', 'Robert'), ('Robert', 'grandfather', 'Clarence')]}]
['son', 'grandfather']