[Milton]'s wife [Mary] has very pretty eyes. [Mary] took her mother, [Amy], out for lunch.
('Milton', 'Amy')
[Milton]'s wife [Mary] has very pretty eyes. [Mary] took her mother, [Amy], out for lunch.
[{('Milton', 'mother-in-law', 'Amy'): [('Milton', 'wife', 'Mary'), ('Mary', 'mother', 'Amy')]}]
['wife', 'mother']