[Mary] called her dad [Nicholas] to pick her up from school. [Milton] was going to meet his wife, [Mary], for lunch.
('Milton', 'Nicholas')
[Milton] was going to meet his wife, [Mary], for lunch. [Mary] called her dad [Nicholas] to pick her up from school.
[{('Milton', 'father-in-law', 'Nicholas'): [('Milton', 'wife', 'Mary'), ('Mary', 'father', 'Nicholas')]}]
['wife', 'father']