[Frances]'s husband [James] and daughter [David] went to the beach while [Bobby], [David]'s son, stayed home to catch up on sleep.
('James', 'Bobby')
[Frances]'s husband [James] and daughter [David] went to the beach while [Bobby], [David]'s son, stayed home to catch up on sleep.
[{('James', 'grandson', 'Bobby'): [('James', 'wife', 'Frances'), ('Frances', 'grandson', 'Bobby')]}, {('Frances', 'grandson', 'Bobby'): [('Frances', 'daughter', 'David'), ('David', 'son', 'Bobby')]}]
['wife', 'daughter', 'son']