[Lena] took her sister [David] out for dinner to celebrate her birthday. [Chris] and his grandfather [James] like to play chess together. [Lena] read her son [Chris] a bedtime story every night.
('David', 'James')
[Lena] took her sister [David] out for dinner to celebrate her birthday. [Lena] read her son [Chris] a bedtime story every night. [Chris] and his grandfather [James] like to play chess together.
[{('David', 'father', 'James'): [('David', 'sister', 'Lena'), ('Lena', 'father', 'James')]}, {('Lena', 'father', 'James'): [('Lena', 'son', 'Chris'), ('Chris', 'grandfather', 'James')]}]
['sister', 'son', 'grandfather']