[John]'s grandfather [Clarence] took him and his sister [April] to the beach to play in the tide pools.
('April', 'Clarence')
[John]'s grandfather [Clarence] took him and his sister [April] to the beach to play in the tide pools.
[{('April', 'grandfather', 'Clarence'): [('April', 'brother', 'John'), ('John', 'grandfather', 'Clarence')]}]
['brother', 'grandfather']