[Marie]'s husband [Robert] and son [Allan] went to the beach with [Robert]'s son, [John]. [John] was the nephew of a man named [Pedro].
('Allan', 'Pedro')
[Marie]'s husband [Robert] and son [Allan] went to the beach with [Robert]'s son, [John]. [John] was the nephew of a man named [Pedro].
[{('Allan', 'uncle', 'Pedro'): [('Allan', 'mother', 'Marie'), ('Marie', 'brother', 'Pedro')]}, {('Marie', 'brother', 'Pedro'): [('Marie', 'son', 'John'), ('John', 'uncle', 'Pedro')]}, {('Marie', 'son', 'John'): [('Marie', 'husband', 'Robert'), ('Robert', 'son', 'John')]}]
['mother', 'husband', 'son', 'uncle']