[Katherine] showed pictures of her son [Bret] to her sister [Michelle] [Michelle] was sewing a sweater for her sister [Helen].
('Helen', 'Bret')
[Michelle] was sewing a sweater for her sister [Helen]. [Katherine] showed pictures of her son [Bret] to her sister [Michelle]
[{('Helen', 'nephew', 'Bret'): [('Helen', 'sister', 'Katherine'), ('Katherine', 'son', 'Bret')]}, {('Helen', 'sister', 'Katherine'): [('Helen', 'sister', 'Michelle'), ('Michelle', 'sister', 'Katherine')]}]