[Tracy] was sewing a sweater for her sister [Beverly]. [Tracy] was playing in the sandbox with her brother [Pedro]. [Pedro]'s brother [Antonio] is a smuggler. He learned how from his sister [Marie].
('Beverly', 'Marie')
[Tracy] was sewing a sweater for her sister [Beverly]. [Tracy] was playing in the sandbox with her brother [Pedro]. [Pedro]'s brother [Antonio] is a smuggler. He learned how from his sister [Marie].
[{('Beverly', 'sister', 'Marie'): [('Beverly', 'brother', 'Pedro'), ('Pedro', 'sister', 'Marie')]}, {('Pedro', 'sister', 'Marie'): [('Pedro', 'brother', 'Antonio'), ('Antonio', 'sister', 'Marie')]}, {('Beverly', 'brother', 'Pedro'): [('Beverly', 'sister', 'Tracy'), ('Tracy', 'brother', 'Pedro')]}]
['sister', 'brother', 'brother', 'sister']