[Nancy] and her son [Robert] went to the store, while [Nancy]'s daughter [Heidi] stayed home.
('Heidi', 'Robert')
[Nancy] and her son [Robert] went to the store, while [Nancy]'s daughter [Heidi] stayed home.
[{('Heidi', 'brother', 'Robert'): [('Heidi', 'mother', 'Nancy'), ('Nancy', 'son', 'Robert')]}]
['mother', 'son']