[Mary] was eating dinner with her sister [Emily]. [Mary]'s brother [Michael] was n't invited.
('Emily', 'Michael')
[Mary] was eating dinner with her sister [Emily]. [Mary]'s brother [Michael] was n't invited.
[{('Emily', 'brother', 'Michael'): [('Emily', 'sister', 'Mary'), ('Mary', 'brother', 'Michael')]}]
['sister', 'brother']