[Robert] has a son named [Mario]. [Mario]'s sister is named [Angelica], and she also has a brother named [Ronald]. [Ronald] was happy to see his aunt [Tracy].
('Robert', 'Tracy')
[Robert] has a son named [Mario]. [Mario]'s sister is named [Angelica], and she also has a brother named [Ronald]. [Ronald] was happy to see his aunt [Tracy].
[{('Robert', 'sister', 'Tracy'): [('Robert', 'son', 'Ronald'), ('Ronald', 'aunt', 'Tracy')]}, {('Robert', 'son', 'Ronald'): [('Robert', 'daughter', 'Angelica'), ('Angelica', 'brother', 'Ronald')]}, {('Robert', 'daughter', 'Angelica'): [('Robert', 'son', 'Mario'), ('Mario', 'sister', 'Angelica')]}]
['son', 'sister', 'brother', 'aunt']