[Robert] went to pick up his son [Ronald] from the baseball practice. [Ronald] invited his uncle [Pedro] to dinner [Emma] asked her father [Antonio] if she could spend the night at her friend's house. [Antonio] and his brother [Robert] are constantly trying to one up each other.
('Emma', 'Pedro')
[Emma] asked her father [Antonio] if she could spend the night at her friend's house. [Antonio] and his brother [Robert] are constantly trying to one up each other. [Robert] went to pick up his son [Ronald] from the baseball practice. [Ronald] invited his uncle [Pedro] to dinner
[{('Emma', 'uncle', 'Pedro'): [('Emma', 'father', 'Antonio'), ('Antonio', 'brother', 'Pedro')]}, {('Antonio', 'brother', 'Pedro'): [('Antonio', 'brother', 'Robert'), ('Robert', 'brother', 'Pedro')]}, {('Robert', 'brother', 'Pedro'): [('Robert', 'son', 'Ronald'), ('Ronald', 'uncle', 'Pedro')]}]
['father', 'brother', 'son', 'uncle']