[David] picked up her son [Bobby] from the mall [David] took her son [Brandon] to school and his grandfather [James] picked him up at then end of the school day.
('Bobby', 'James')
[David] picked up her son [Bobby] from the mall [David] took her son [Brandon] to school and his grandfather [James] picked him up at then end of the school day.
[{('Bobby', 'grandfather', 'James'): [('Bobby', 'mother', 'David'), ('David', 'father', 'James')]}, {('David', 'father', 'James'): [('David', 'son', 'Brandon'), ('Brandon', 'grandfather', 'James')]}]
['mother', 'son', 'grandfather']