[Robert] made a grilled cheese for his son [Mario]. [Mario]'s brother [John] ate a salad. [Louis] took his son [Samuel] to soccer practice. [John] and his uncle [Louis] are two of the best poker players in town.
('Robert', 'Samuel')
[Robert] made a grilled cheese for his son [Mario]. [Mario]'s brother [John] ate a salad. [John] and his uncle [Louis] are two of the best poker players in town. [Louis] took his son [Samuel] to soccer practice.
[{('Robert', 'nephew', 'Samuel'): [('Robert', 'brother', 'Louis'), ('Louis', 'son', 'Samuel')]}, {('Robert', 'brother', 'Louis'): [('Robert', 'son', 'John'), ('John', 'uncle', 'Louis')]}, {('Robert', 'son', 'John'): [('Robert', 'son', 'Mario'), ('Mario', 'brother', 'John')]}]
['son', 'brother', 'uncle', 'son']