[Dale] and his son [Tony] built a model rocket. [Dale]'s sister [Amy] was proud of them.
('Tony', 'Amy')
[Dale] and his son [Tony] built a model rocket. [Dale]'s sister [Amy] was proud of them.
[{('Tony', 'aunt', 'Amy'): [('Tony', 'father', 'Dale'), ('Dale', 'sister', 'Amy')]}]
['father', 'sister']