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