[Clarence] went bike riding his grandson [John]. [John]'s father [George] was skateboarding.
('George', 'Clarence')
[Clarence] went bike riding his grandson [John]. [John]'s father [George] was skateboarding.
[{('George', 'father', 'Clarence'): [('George', 'son', 'John'), ('John', 'grandfather', 'Clarence')]}]
['son', 'grandfather']