[Mary] liked to play hide and seek with her son [Herman]. [Herman] decided to take his son, [Arthur], on a ski vacation.
('Mary', 'Arthur')
[Mary] liked to play hide and seek with her son [Herman]. [Herman] decided to take his son, [Arthur], on a ski vacation.
[{('Mary', 'grandson', 'Arthur'): [('Mary', 'son', 'Herman'), ('Herman', 'son', 'Arthur')]}]