[Linda] took her younger sister [Heidi] to the carnival last weekend. [Linda] called her brother, [Robert], up to see how he was doing after surgery.
('Heidi', 'Robert')
[Linda] took her younger sister [Heidi] to the carnival last weekend. [Linda] called her brother, [Robert], up to see how he was doing after surgery.
[{('Heidi', 'brother', 'Robert'): [('Heidi', 'sister', 'Linda'), ('Linda', 'brother', 'Robert')]}]
['sister', 'brother']