story: [Minnie] took her son [William] to the mall to shop for school clothes. [Nancy] went out to dinner with her sister [Minnie], and [Minnie]'s daughter [Ellen].
query: ('Nancy', 'Ellen')
clean_story: [Nancy] went out to dinner with her sister [Minnie], and [Minnie]'s daughter [Ellen].
proof_state: [{('Nancy', 'niece', 'Ellen'): [('Nancy', 'sister', 'Minnie'), ('Minnie', 'daughter', 'Ellen')]}]