[Amy] bought her son [Glen] a car. [Glen]'s sister [Emily] was jealous.
('Emily', 'Amy')
[Amy] bought her son [Glen] a car. [Glen]'s sister [Emily] was jealous.
[{('Emily', 'mother', 'Amy'): [('Emily', 'brother', 'Glen'), ('Glen', 'mother', 'Amy')]}]
['brother', 'mother']