[Theresa] does n't like having to babysit her younger brother, [George]. [George] helped his brother, [Nicholas], study for the chemistry exam.
('Theresa', 'Nicholas')
[Theresa] does n't like having to babysit her younger brother, [George]. [George] helped his brother, [Nicholas], study for the chemistry exam.
[{('Theresa', 'brother', 'Nicholas'): [('Theresa', 'brother', 'George'), ('George', 'brother', 'Nicholas')]}]
['brother', 'brother']