[Nancy] and her sister [Lillian] were getting together this weekend so that they could go hiking together they had n't spent time together alone in a while. [Amy] needed to go to the store. [Amy] asked her sister [Nancy] for a ride.
('Lillian', 'Amy')
[Nancy] and her sister [Lillian] were getting together this weekend so that they could go hiking together they had n't spent time together alone in a while. [Amy] needed to go to the store. [Amy] asked her sister [Nancy] for a ride.
[{('Lillian', 'sister', 'Amy'): [('Lillian', 'sister', 'Nancy'), ('Nancy', 'sister', 'Amy')]}]
['sister', 'sister']