[Clarence] taught his granddaughter, [Heidi], how to fish. [Robert] is going to the arcade with his sister, [Heidi].
('Robert', 'Clarence')
[Robert] is going to the arcade with his sister, [Heidi]. [Clarence] taught his granddaughter, [Heidi], how to fish.
[{('Robert', 'grandfather', 'Clarence'): [('Robert', 'sister', 'Heidi'), ('Heidi', 'grandfather', 'Clarence')]}]
['sister', 'grandfather']