[Herman] invited his daughter [Monet] and her husband [Arthur] over for dinner.
('Herman', 'Arthur')
[Herman] invited his daughter [Monet] and her husband [Arthur] over for dinner.
[{('Herman', 'son-in-law', 'Arthur'): [('Herman', 'daughter', 'Monet'), ('Monet', 'husband', 'Arthur')]}]