[Nancy] gave her brother [Nicholas] a new sweater for Christmas. [Nancy] took her younger sister [Theresa] to the carnival last weekend.
('Theresa', 'Nicholas')
[Nancy] took her younger sister [Theresa] to the carnival last weekend. [Nancy] gave her brother [Nicholas] a new sweater for Christmas.
[{('Theresa', 'brother', 'Nicholas'): [('Theresa', 'sister', 'Nancy'), ('Nancy', 'brother', 'Nicholas')]}]
['sister', 'brother']