[Marie] drove her son [Allan] to his soccer game. [Mario] brought home straight A's to his father [Robert]. [Allan] brought home straight C's to his father [Robert]. [Marie] took her sister [Tracy] out for dinner to celebrate her birthday.
('Tracy', 'Mario')
[Marie] took her sister [Tracy] out for dinner to celebrate her birthday. [Marie] drove her son [Allan] to his soccer game. [Mario] brought home straight A's to his father [Robert]. [Allan] brought home straight C's to his father [Robert].
[{('Tracy', 'nephew', 'Mario'): [('Tracy', 'sister', 'Marie'), ('Marie', 'son', 'Mario')]}, {('Marie', 'son', 'Mario'): [('Marie', 'son', 'Allan'), ('Allan', 'brother', 'Mario')]}, {('Allan', 'brother', 'Mario'): [('Allan', 'father', 'Robert'), ('Robert', 'son', 'Mario')]}]
['sister', 'son', 'father', 'son']