[Lorraine] invited her sisters, [Heidi] and [Louise], to a party.
('Louise', 'Heidi')
[Lorraine] invited her sisters, [Heidi] and [Louise], to a party.
[{('Louise', 'sister', 'Heidi'): [('Louise', 'sister', 'Lorraine'), ('Lorraine', 'sister', 'Heidi')]}]
['sister', 'sister']