[Pedro] and his wife [Dorothy] will be at the play. [Dorothy] was mad at her brother [Robert], because [Robert] had called her fat. [Robert] 'son [John] and [John]'s grandfather [Harold] went on a cruise together.
('Pedro', 'Harold')
[Pedro] and his wife [Dorothy] will be at the play. [Dorothy] was mad at her brother [Robert], because [Robert] had called her fat. [Robert] 'son [John] and [John]'s grandfather [Harold] went on a cruise together.
[{('Pedro', 'father-in-law', 'Harold'): [('Pedro', 'wife', 'Dorothy'), ('Dorothy', 'father', 'Harold')]}, {('Dorothy', 'father', 'Harold'): [('Dorothy', 'brother', 'Robert'), ('Robert', 'father', 'Harold')]}, {('Robert', 'father', 'Harold'): [('Robert', 'son', 'John'), ('John', 'grandfather', 'Harold')]}]
['wife', 'brother', 'son', 'grandfather']