[Katherine] and [Matthew] had a picnic at the park. They had sandwiches and salad. [Michelle] and her sister [Katherine] braided each other's hair before school. [Helen] is a woman with a sister named [Michelle].
('Matthew', 'Helen')
[Katherine] and [Matthew] had a picnic at the park. They had sandwiches and salad. [Michelle] and her sister [Katherine] braided each other's hair before school. [Helen] is a woman with a sister named [Michelle].
[{('Matthew', 'sister', 'Helen'): [('Matthew', 'sister', 'Michelle'), ('Michelle', 'sister', 'Helen')]}, {('Matthew', 'sister', 'Michelle'): [('Matthew', 'sister', 'Katherine'), ('Katherine', 'sister', 'Michelle')]}]