att*!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!C!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!r bo { this.z - x }

assert]e!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!find_last_not_ofb::z
defred(x) { this.z - x }
assert]equal(8, x.fred(3))
