Ah, nice catch.  So these should probably be replace with a member variable on the step subclass.  I'm under the impression that statistics are completely unused outside of a few built-in steps, which is why I wanted to remove them.  If that's not the case, then I could certainly change the spelling from `self.step_status.setStatistic` to `self.setStatistic` in new-style steps.  What do you think?