[Nancy] took her sister [Theresa] out for dinner to celebrate her birthday. [Nancy] has a son named [Kevin].
('Theresa', 'Kevin')
[Nancy] took her sister [Theresa] out for dinner to celebrate her birthday. [Nancy] has a son named [Kevin].
[{('Theresa', 'nephew', 'Kevin'): [('Theresa', 'sister', 'Nancy'), ('Nancy', 'son', 'Kevin')]}]
['sister', 'son']