[Heidi]'s sister [Lorraine] painted a picture for [Heidi]'s mother, [Nancy].
('Nancy', 'Lorraine')
[Heidi]'s sister [Lorraine] painted a picture for [Heidi]'s mother, [Nancy].
[{('Nancy', 'daughter', 'Lorraine'): [('Nancy', 'daughter', 'Heidi'), ('Heidi', 'sister', 'Lorraine')]}]
['daughter', 'sister']