[Dennis] took a cab to the mall with his sister [Natalia]. [Natalia]'s sister [Jennifer] drove herself there.
('Jennifer', 'Dennis')
[Dennis] took a cab to the mall with his sister [Natalia]. [Natalia]'s sister [Jennifer] drove herself there.
[{('Jennifer', 'brother', 'Dennis'): [('Jennifer', 'sister', 'Natalia'), ('Natalia', 'brother', 'Dennis')]}]
['sister', 'brother']