[Nancy]'s son [Jacob] and brother [George] came to her birthday party last weekend.
('George', 'Jacob')
[Nancy]'s son [Jacob] and brother [George] came to her birthday party last weekend.
[{('George', 'nephew', 'Jacob'): [('George', 'sister', 'Nancy'), ('Nancy', 'son', 'Jacob')]}]
['sister', 'son']