[Douglas]'s grandfather [Clarence] helped his mother, [Lillian], repaint her house today.
('Lillian', 'Clarence')
[Douglas]'s grandfather [Clarence] helped his mother, [Lillian], repaint her house today.
[{('Lillian', 'father', 'Clarence'): [('Lillian', 'son', 'Douglas'), ('Douglas', 'grandfather', 'Clarence')]}]
['son', 'grandfather']