[Natalia] invited her sisters, [Mary] and [Jennifer], to a party.
('Jennifer', 'Mary')
[Natalia] invited her sisters, [Mary] and [Jennifer], to a party.
[{('Jennifer', 'sister', 'Mary'): [('Jennifer', 'sister', 'Natalia'), ('Natalia', 'sister', 'Mary')]}]
['sister', 'sister']