[Dennis] and his brother [Michael] are very close. [Michael] does not get along well with his sister [Natalia].
('Dennis', 'Natalia')
[Dennis] and his brother [Michael] are very close. [Michael] does not get along well with his sister [Natalia].
[{('Dennis', 'sister', 'Natalia'): [('Dennis', 'brother', 'Michael'), ('Michael', 'sister', 'Natalia')]}]
['brother', 'sister']