[Robert] borrowed some money from his sister [Tracy]. [Heather] begged her parents [Dorothy] and [Pedro] to let her aunt [Tracy] come over
('Robert', 'Heather')
[Robert] borrowed some money from his sister [Tracy]. [Heather] begged her parents [Dorothy] and [Pedro] to let her aunt [Tracy] come over
[{('Robert', 'niece', 'Heather'): [('Robert', 'brother', 'Pedro'), ('Pedro', 'daughter', 'Heather')]}, {('Pedro', 'daughter', 'Heather'): [('Pedro', 'wife', 'Dorothy'), ('Dorothy', 'daughter', 'Heather')]}, {('Robert', 'brother', 'Pedro'): [('Robert', 'sister', 'Tracy'), ('Tracy', 'brother', 'Pedro')]}]
['sister', 'brother', 'wife', 'daughter']