[Lillian] went shopping with her daughter [Ann]. [Ann]'s sister [Janet] was too busy to join them.
('Janet', 'Lillian')
[Lillian] went shopping with her daughter [Ann]. [Ann]'s sister [Janet] was too busy to join them.
[{('Janet', 'mother', 'Lillian'): [('Janet', 'sister', 'Ann'), ('Ann', 'mother', 'Lillian')]}]
['sister', 'mother']