[Hugh] bought a book for his father [James]. [Martha] went to the theme park with her mother [Lena] and grandfather [James].
('Lena', 'Hugh')
[Martha] went to the theme park with her mother [Lena] and grandfather [James]. [Hugh] bought a book for his father [James].
[{('Lena', 'brother', 'Hugh'): [('Lena', 'father', 'James'), ('James', 'son', 'Hugh')]}, {('Lena', 'father', 'James'): [('Lena', 'daughter', 'Martha'), ('Martha', 'grandfather', 'James')]}]
['daughter', 'grandfather', 'son']