[Milton] and his brother [Glen] liked to eat pizza but [Glen]'s sister [Emily] liked to eat tacos.
('Milton', 'Emily')
[Milton] and his brother [Glen] liked to eat pizza but [Glen]'s sister [Emily] liked to eat tacos.
[{('Milton', 'sister', 'Emily'): [('Milton', 'brother', 'Glen'), ('Glen', 'sister', 'Emily')]}]
['brother', 'sister']