[Robert] went to pick up his son [Allan] from the baseball practice. [Allan] and his sister [Angelica] love to play video games. [Angelica] went on a vacation with her brother [Mario]. [Robert] took his sister [Dorothy] out to dinner for her birthday.
('Dorothy', 'Mario')
[Robert] took his sister [Dorothy] out to dinner for her birthday. [Robert] went to pick up his son [Allan] from the baseball practice. [Allan] and his sister [Angelica] love to play video games. [Angelica] went on a vacation with her brother [Mario].
[{('Dorothy', 'nephew', 'Mario'): [('Dorothy', 'brother', 'Robert'), ('Robert', 'son', 'Mario')]}, {('Robert', 'son', 'Mario'): [('Robert', 'son', 'Allan'), ('Allan', 'brother', 'Mario')]}, {('Allan', 'brother', 'Mario'): [('Allan', 'sister', 'Angelica'), ('Angelica', 'brother', 'Mario')]}]
['brother', 'son', 'sister', 'brother']