[Jacob] went skiing with his brother [Jeff]. [Jeff]'s sister [Linda] watched from the ski lodge.
('Linda', 'Jacob')
[Jacob] went skiing with his brother [Jeff]. [Jeff]'s sister [Linda] watched from the ski lodge.
[{('Linda', 'brother', 'Jacob'): [('Linda', 'brother', 'Jeff'), ('Jeff', 'brother', 'Jacob')]}]
['brother', 'brother']