[Richard] and his brother [Leonard] went to the arcade. They had a wonderful time. [Natasha] and her grandfather [James] went to the museum. [Natasha] was bored, so they soon left. [Richard] and his sister [Natasha] took their father out to eat for his birthday. They had a great time.
('Leonard', 'James')
[Richard] and his brother [Leonard] went to the arcade. They had a wonderful time. [Richard] and his sister [Natasha] took their father out to eat for his birthday. They had a great time. [Natasha] and her grandfather [James] went to the museum. [Natasha] was bored, so they soon left.
[{('Leonard', 'grandfather', 'James'): [('Leonard', 'brother', 'Richard'), ('Richard', 'grandfather', 'James')]}, {('Richard', 'grandfather', 'James'): [('Richard', 'sister', 'Natasha'), ('Natasha', 'grandfather', 'James')]}]
['brother', 'sister', 'grandfather']