[Milton] went to the grocery store for his brother [Michael], because he broke his leg. [Milton] braided his sister [Natalia]'s hair.
('Michael', 'Natalia')
[Milton] went to the grocery store for his brother [Michael], because he broke his leg. [Milton] braided his sister [Natalia]'s hair.
[{('Michael', 'sister', 'Natalia'): [('Michael', 'brother', 'Milton'), ('Milton', 'sister', 'Natalia')]}]
['brother', 'sister']