[Tony] wanted to go to the park with his sister [Charlotte]. [Charlotte] said she'd rather go swimming with her sister [June] instead.
('Tony', 'June')
[Tony] wanted to go to the park with his sister [Charlotte]. [Charlotte] said she'd rather go swimming with her sister [June] instead.
[{('Tony', 'sister', 'June'): [('Tony', 'sister', 'Charlotte'), ('Charlotte', 'sister', 'June')]}]
['sister', 'sister']