[Robert] and his son [Ronald] went to visit [Robert]'s sister [Beverly] Saturday. They ate lunch and played video games. [Ronald] went to a piano concert with his aunt [Dorothy]. [Nettie] was celebrating her birthday with her mother [Beverly].
('Nettie', 'Dorothy')
[Nettie] was celebrating her birthday with her mother [Beverly]. [Robert] and his son [Ronald] went to visit [Robert]'s sister [Beverly] Saturday. They ate lunch and played video games. [Ronald] went to a piano concert with his aunt [Dorothy].
[{('Nettie', 'aunt', 'Dorothy'): [('Nettie', 'mother', 'Beverly'), ('Beverly', 'sister', 'Dorothy')]}, {('Beverly', 'sister', 'Dorothy'): [('Beverly', 'brother', 'Robert'), ('Robert', 'sister', 'Dorothy')]}, {('Robert', 'sister', 'Dorothy'): [('Robert', 'son', 'Ronald'), ('Ronald', 'aunt', 'Dorothy')]}]
['mother', 'brother', 'son', 'aunt']