[James] and his sister [Rosetta] were twins. Still, they did n't look very much alike. [James] and his sister [Belva] stood in line at the fair.
('Belva', 'Rosetta')
[James] and his sister [Belva] stood in line at the fair. [James] and his sister [Rosetta] were twins. Still, they did n't look very much alike.
[{('Belva', 'sister', 'Rosetta'): [('Belva', 'brother', 'James'), ('James', 'sister', 'Rosetta')]}]
['brother', 'sister']