[Amy] asked her son [Dennis] for help. [Dennis]'s sister [Mary] helped instead.
('Mary', 'Amy')
[Amy] asked her son [Dennis] for help. [Dennis]'s sister [Mary] helped instead.
[{('Mary', 'mother', 'Amy'): [('Mary', 'brother', 'Dennis'), ('Dennis', 'mother', 'Amy')]}]
['brother', 'mother']