[Andrea] went to the store with her sister [April]. Later that day, [Andrea] had tea with her sister [Janet].
('Janet', 'April')
[Andrea] went to the store with her sister [April]. Later that day, [Andrea] had tea with her sister [Janet].
[{('Janet', 'sister', 'April'): [('Janet', 'sister', 'Andrea'), ('Andrea', 'sister', 'April')]}]
['sister', 'sister']