[Erika] went to visit her grandfather [Harold] for his birthday. Her sister [Laura] could n't come as she was busy. [Robert] and his sister [Tracy] are decorating for a party. [Tracy]'s daughter [Laura] thinks the party will be fun.
('Robert', 'Harold')
[Robert] and his sister [Tracy] are decorating for a party. [Tracy]'s daughter [Laura] thinks the party will be fun. [Erika] went to visit her grandfather [Harold] for his birthday. Her sister [Laura] could n't come as she was busy.
[{('Robert', 'father', 'Harold'): [('Robert', 'sister', 'Tracy'), ('Tracy', 'father', 'Harold')]}, {('Tracy', 'father', 'Harold'): [('Tracy', 'daughter', 'Erika'), ('Erika', 'grandfather', 'Harold')]}, {('Tracy', 'daughter', 'Erika'): [('Tracy', 'daughter', 'Laura'), ('Laura', 'sister', 'Erika')]}]
['sister', 'daughter', 'sister', 'grandfather']