[Lena] took her son [Chris] to the park. [Lena] invited her mother, [Frances], to dinner and extended the invitation to [Frances]'s son, [Hugh].
('Chris', 'Hugh')
[Lena] took her son [Chris] to the park. [Lena] invited her mother, [Frances], to dinner and extended the invitation to [Frances]'s son, [Hugh].
[{('Chris', 'uncle', 'Hugh'): [('Chris', 'mother', 'Lena'), ('Lena', 'brother', 'Hugh')]}, {('Lena', 'brother', 'Hugh'): [('Lena', 'mother', 'Frances'), ('Frances', 'son', 'Hugh')]}]
['mother', 'mother', 'son']