[Louis] went to the store with his brother, [Pedro]. [Robert]'s brother, [Pedro], recently got elected as a senator. [Beverly]'s brother [Antonio] was going to be the star in the new show. [Robert] was sad to learn that his sister [Beverly] was not going to make it to dinner like they had planned.
('Louis', 'Antonio')
[Louis] went to the store with his brother, [Pedro]. [Robert]'s brother, [Pedro], recently got elected as a senator. [Robert] was sad to learn that his sister [Beverly] was not going to make it to dinner like they had planned. [Beverly]'s brother [Antonio] was going to be the star in the new show.
[{('Louis', 'brother', 'Antonio'): [('Louis', 'brother', 'Pedro'), ('Pedro', 'brother', 'Antonio')]}, {('Pedro', 'brother', 'Antonio'): [('Pedro', 'brother', 'Robert'), ('Robert', 'brother', 'Antonio')]}, {('Robert', 'brother', 'Antonio'): [('Robert', 'sister', 'Beverly'), ('Beverly', 'brother', 'Antonio')]}]
['brother', 'brother', 'sister', 'brother']