story: [James] went to the park with his father, [Jason]. [Dan]'s father, [James], bought him some ice cream.
query: ('Dan', 'Jason')
clean_story: [Dan]'s father, [James], bought him some ice cream. [James] went to the park with his father, [Jason].
proof_state: [{('Dan', 'grandfather', 'Jason'): [('Dan', 'father', 'James'), ('James', 'father', 'Jason')]}]