[Joshua] took his son [Clarence] to soccer practice. [James] took his son, [Joshua] to the movies with [David], who's father is [James].
('David', 'Clarence')
[James] took his son, [Joshua] to the movies with [David], who's father is [James]. [Joshua] took his son [Clarence] to soccer practice.
[{('David', 'nephew', 'Clarence'): [('David', 'brother', 'Joshua'), ('Joshua', 'son', 'Clarence')]}, {('David', 'brother', 'Joshua'): [('David', 'father', 'James'), ('James', 'son', 'Joshua')]}]
['father', 'son', 'son']