[Nancy] loves her brother [George]. [Clarence] bought a book for his son [George].
('Nancy', 'Clarence')
[Nancy] loves her brother [George]. [Clarence] bought a book for his son [George].
[{('Nancy', 'father', 'Clarence'): [('Nancy', 'brother', 'George'), ('George', 'father', 'Clarence')]}]
['brother', 'father']