[Lena] went to the lake with her son [Chris] and her father [James]. [James] was sad that his other daughter [David] could not join them since she was out of town.
('David', 'Chris')
[Lena] went to the lake with her son [Chris] and her father [James]. [James] was sad that his other daughter [David] could not join them since she was out of town.
[{('David', 'nephew', 'Chris'): [('David', 'sister', 'Lena'), ('Lena', 'son', 'Chris')]}, {('David', 'sister', 'Lena'): [('David', 'father', 'James'), ('James', 'daughter', 'Lena')]}]
['father', 'daughter', 'son']