[Lillian]'s son [John] and brother [Nicholas] came to her birthday party last weekend.
('Nicholas', 'John')
[Lillian]'s son [John] and brother [Nicholas] came to her birthday party last weekend.
[{('Nicholas', 'nephew', 'John'): [('Nicholas', 'sister', 'Lillian'), ('Lillian', 'son', 'John')]}]
['sister', 'son']