[Janet]'s mother [Lillian] had given her a gift certificate so [Janet] took her sister [Andrea] out to eat.
('Andrea', 'Lillian')
[Janet]'s mother [Lillian] had given her a gift certificate so [Janet] took her sister [Andrea] out to eat.
[{('Andrea', 'mother', 'Lillian'): [('Andrea', 'sister', 'Janet'), ('Janet', 'mother', 'Lillian')]}]
['sister', 'mother']