[Nancy] took her son [Jacob] to the park yesterday. [Jacob]'s sister [Heidi] was playing at a friends house and did n't get to go.
('Heidi', 'Nancy')
[Nancy] took her son [Jacob] to the park yesterday. [Jacob]'s sister [Heidi] was playing at a friends house and did n't get to go.
[{('Heidi', 'mother', 'Nancy'): [('Heidi', 'brother', 'Jacob'), ('Jacob', 'mother', 'Nancy')]}]
['brother', 'mother']