[April] and her sister [Andrea] braided each other's hair before school. [Jerry] took his sister [April] out to dinner for her birthday.
('Andrea', 'Jerry')
[April] and her sister [Andrea] braided each other's hair before school. [Jerry] took his sister [April] out to dinner for her birthday.
[{('Andrea', 'brother', 'Jerry'): [('Andrea', 'sister', 'April'), ('April', 'brother', 'Jerry')]}]
['sister', 'brother']