[Michael] liked to talk about his sister, [Emily]. [Glen] and his brother [Michael] were rarely seen apart.
('Glen', 'Emily')
[Glen] and his brother [Michael] were rarely seen apart. [Michael] liked to talk about his sister, [Emily].
[{('Glen', 'sister', 'Emily'): [('Glen', 'brother', 'Michael'), ('Michael', 'sister', 'Emily')]}]
['brother', 'sister']