[Jacob]'s mother [Nancy] made a cake for his birthday and her other son [Jeff] ate a piece of it.
('Jacob', 'Jeff')
[Jacob]'s mother [Nancy] made a cake for his birthday and her other son [Jeff] ate a piece of it.
[{('Jacob', 'brother', 'Jeff'): [('Jacob', 'mother', 'Nancy'), ('Nancy', 'son', 'Jeff')]}]
['mother', 'son']