[Dennis] and his father [Nicholas] went to the golf course in town on Saturday and had a great time. [Clarence] decided to take his son, [Nicholas], on a ski vacation.
('Clarence', 'Dennis')
[Clarence] decided to take his son, [Nicholas], on a ski vacation. [Dennis] and his father [Nicholas] went to the golf course in town on Saturday and had a great time.
[{('Clarence', 'grandson', 'Dennis'): [('Clarence', 'son', 'Nicholas'), ('Nicholas', 'son', 'Dennis')]}]
['son', 'son']