[Douglas] loved his mother, [Lillian]. [Dale] and his sister [Lillian] went to the park.
('Dale', 'Douglas')
[Dale] and his sister [Lillian] went to the park. [Douglas] loved his mother, [Lillian].
[{('Dale', 'nephew', 'Douglas'): [('Dale', 'sister', 'Lillian'), ('Lillian', 'son', 'Douglas')]}]
['sister', 'son']