[Robert] and his brother [Louis] went to see a baseball game on Friday and had a great time. [Robert] drove to his sister [Tracy]'s house, where he saw [Tracy]'s son [Aaron] and his sister [Bettie].
('Louis', 'Bettie')
[Robert] and his brother [Louis] went to see a baseball game on Friday and had a great time. [Robert] drove to his sister [Tracy]'s house, where he saw [Tracy]'s son [Aaron] and his sister [Bettie].
[{('Louis', 'niece', 'Bettie'): [('Louis', 'sister', 'Tracy'), ('Tracy', 'daughter', 'Bettie')]}, {('Tracy', 'daughter', 'Bettie'): [('Tracy', 'son', 'Aaron'), ('Aaron', 'sister', 'Bettie')]}, {('Louis', 'sister', 'Tracy'): [('Louis', 'brother', 'Robert'), ('Robert', 'sister', 'Tracy')]}]
['brother', 'sister', 'son', 'sister']