[Mary] and her father [Nicholas] love to go skiing. Often, [Nicholas] will invite his mother [Ashley] to join them.
('Mary', 'Ashley')
[Mary] and her father [Nicholas] love to go skiing. Often, [Nicholas] will invite his mother [Ashley] to join them.
[{('Mary', 'grandmother', 'Ashley'): [('Mary', 'father', 'Nicholas'), ('Nicholas', 'mother', 'Ashley')]}]
['father', 'mother']