[Mary], [Michael]'s sister, was helping him around the house. Her brother [Dennis] was helping out too.
('Michael', 'Dennis')
[Mary], [Michael]'s sister, was helping him around the house. Her brother [Dennis] was helping out too.
[{('Michael', 'brother', 'Dennis'): [('Michael', 'sister', 'Mary'), ('Mary', 'brother', 'Dennis')]}]
['sister', 'brother']