[Mary] invited her grandfather [Clarence] and her sister [Jennifer] over to her house for dinner.
('Jennifer', 'Clarence')
[Mary] invited her grandfather [Clarence] and her sister [Jennifer] over to her house for dinner.
[{('Jennifer', 'grandfather', 'Clarence'): [('Jennifer', 'sister', 'Mary'), ('Mary', 'grandfather', 'Clarence')]}]
['sister', 'grandfather']