[Frances] and her husband [James] invited their son [Hugh] to dinner. [Hugh] also took his son [Bobby] with him.
('James', 'Bobby')
[Frances] and her husband [James] invited their son [Hugh] to dinner. [Hugh] also took his son [Bobby] with him.
[{('James', 'grandson', 'Bobby'): [('James', 'son', 'Hugh'), ('Hugh', 'son', 'Bobby')]}, {('James', 'son', 'Hugh'): [('James', 'wife', 'Frances'), ('Frances', 'son', 'Hugh')]}]
['wife', 'son', 'son']