story: [Michael] is taking his son [Chad] out for coffee. [Michael] went hunting with his son, [Robert].
query: ('Robert', 'Chad')
clean_story: [Michael] went hunting with his son, [Robert]. [Michael] is taking his son [Chad] out for coffee.
proof_state: [{('Robert', 'brother', 'Chad'): [('Robert', 'father', 'Michael'), ('Michael', 'son', 'Chad')]}]