[Amy] visited her brother [Dale] in New York. His sister [Lillian] was there too.
('Lillian', 'Amy')
[Amy] visited her brother [Dale] in New York. His sister [Lillian] was there too.
[{('Lillian', 'sister', 'Amy'): [('Lillian', 'brother', 'Dale'), ('Dale', 'sister', 'Amy')]}]
['brother', 'sister']