[George] taught his daughter, [Ann], how to ride a bike. [George] went to pick up his son [John] from the baseball practice.
('Ann', 'John')
[George] taught his daughter, [Ann], how to ride a bike. [George] went to pick up his son [John] from the baseball practice.
[{('Ann', 'brother', 'John'): [('Ann', 'father', 'George'), ('George', 'son', 'John')]}]
['father', 'son']