[Dennis] and his father [Nicholas] played video games all day last Saturday. [Nicholas]'s mother [Ashley] wanted to surprise him for his birthday, so she baked him a cake.
('Dennis', 'Ashley')
[Dennis] and his father [Nicholas] played video games all day last Saturday. [Nicholas]'s mother [Ashley] wanted to surprise him for his birthday, so she baked him a cake.
[{('Dennis', 'grandmother', 'Ashley'): [('Dennis', 'father', 'Nicholas'), ('Nicholas', 'mother', 'Ashley')]}]
['father', 'mother']