[Amy] walked to the park with her son [Milton]. [Milton]'s wife [Mary] was at the park waiting for them.
('Mary', 'Amy')
[Amy] walked to the park with her son [Milton]. [Milton]'s wife [Mary] was at the park waiting for them.
[{('Mary', 'mother-in-law', 'Amy'): [('Mary', 'husband', 'Milton'), ('Milton', 'mother', 'Amy')]}]
['husband', 'mother']