[George] went to the parade with his wife [Lillian] and his son [Douglas].
('Lillian', 'Douglas')
[George] went to the parade with his wife [Lillian] and his son [Douglas].
[{('Lillian', 'son', 'Douglas'): [('Lillian', 'husband', 'George'), ('George', 'son', 'Douglas')]}]
['husband', 'son']