[George]'s son, [John], loves trains. [George]'s sister, [Nancy], got him a nice model trail set for his birthday.
('John', 'Nancy')
[George]'s son, [John], loves trains. [George]'s sister, [Nancy], got him a nice model trail set for his birthday.
[{('John', 'aunt', 'Nancy'): [('John', 'father', 'George'), ('George', 'sister', 'Nancy')]}]
['father', 'sister']