[Wayne] watched his son [Jacob] play catch. [Jacob] tossed the ball back and fourth with his brother [Jeff].
('Wayne', 'Jeff')
[Wayne] watched his son [Jacob] play catch. [Jacob] tossed the ball back and fourth with his brother [Jeff].
[{('Wayne', 'son', 'Jeff'): [('Wayne', 'son', 'Jacob'), ('Jacob', 'brother', 'Jeff')]}]
['son', 'brother']