[Theresa] went to the store with her sister [Amy]. Later that day, [Theresa] had tea with her sister [Lillian].
('Lillian', 'Amy')
[Theresa] went to the store with her sister [Amy]. Later that day, [Theresa] had tea with her sister [Lillian].
[{('Lillian', 'sister', 'Amy'): [('Lillian', 'sister', 'Theresa'), ('Theresa', 'sister', 'Amy')]}]
['sister', 'sister']