[Nancy], [Nicholas]'s sister, enjoys taking her daughter, [Heidi], to the park.
('Nicholas', 'Heidi')
[Nancy], [Nicholas]'s sister, enjoys taking her daughter, [Heidi], to the park.
[{('Nicholas', 'niece', 'Heidi'): [('Nicholas', 'sister', 'Nancy'), ('Nancy', 'daughter', 'Heidi')]}]
['sister', 'daughter']