If we look at the status quo structure, there are no checks above this point to make sure that classifiers exist for this AIGradingWorkflow before trying to grade.   I thought it would be an info call because it doesn't reflect an error from this code (or really from anywhere), but a disruption in the logical flow that we anticipate.  If for some reason classifiers don't exist for a given workflow, (say they have yet to complete training, but submissions have opened), is that something that we want to log a stack trace for?