[Clarence] took his son [George] out for ice cream. [Clarence]'s son [Nicholas], was still in school.
('Nicholas', 'George')
[Clarence] took his son [George] out for ice cream. [Clarence]'s son [Nicholas], was still in school.
[{('Nicholas', 'brother', 'George'): [('Nicholas', 'father', 'Clarence'), ('Clarence', 'son', 'George')]}]
['father', 'son']