[Fernando] took his mother [Constance] and his sister [Geraldine] out to lunch.
('Constance', 'Geraldine')
[Fernando] took his mother [Constance] and his sister [Geraldine] out to lunch.
[{('Constance', 'daughter', 'Geraldine'): [('Constance', 'son', 'Fernando'), ('Fernando', 'sister', 'Geraldine')]}]