[Tracy], [Pedro]'s sister, was helping him around the house. Her brother [Robert] was helping out too. [Pedro] got mad at his brother [Louis] after he stole his pretzels. [Pedro] and his brother [Louis] were rarely seen apart.
('Pedro', 'Robert')
[Pedro] and his brother [Louis] were rarely seen apart. [Pedro] got mad at his brother [Louis] after he stole his pretzels. [Tracy], [Pedro]'s sister, was helping him around the house. Her brother [Robert] was helping out too.
[{('Pedro', 'brother', 'Robert'): [('Pedro', 'brother', 'Louis'), ('Louis', 'brother', 'Robert')]}, {('Louis', 'brother', 'Robert'): [('Louis', 'sister', 'Tracy'), ('Tracy', 'brother', 'Robert')]}, {('Louis', 'sister', 'Tracy'): [('Louis', 'brother', 'Pedro'), ('Pedro', 'sister', 'Tracy')]}]
['brother', 'brother', 'sister', 'brother']