[Mario]'s sister, [Elsie], took her Mom, [Marie] to see her sister, [Tracy]. [Robert] took his son [Mario] to soccer practice.
('Robert', 'Tracy')
[Robert] took his son [Mario] to soccer practice. [Mario]'s sister, [Elsie], took her Mom, [Marie] to see her sister, [Tracy].
[{('Robert', 'sister', 'Tracy'): [('Robert', 'daughter', 'Elsie'), ('Elsie', 'aunt', 'Tracy')]}, {('Elsie', 'aunt', 'Tracy'): [('Elsie', 'mother', 'Marie'), ('Marie', 'sister', 'Tracy')]}, {('Robert', 'daughter', 'Elsie'): [('Robert', 'son', 'Mario'), ('Mario', 'sister', 'Elsie')]}]
['son', 'sister', 'mother', 'sister']