[Nicholas] bought a present for his son [Dennis]. His daughter [Mary] felt let out.
('Mary', 'Dennis')
[Nicholas] bought a present for his son [Dennis]. His daughter [Mary] felt let out.
[{('Mary', 'brother', 'Dennis'): [('Mary', 'father', 'Nicholas'), ('Nicholas', 'son', 'Dennis')]}]
['father', 'son']