Sorry, yes, I did confused those two names (which obviously is a bad sign). ``is_valid`` can be used to indicate whether a given method should be executed regardless of if the item has ``failed``. In other words, if ``is_valid==False`` then the method will execute even if the item being processed has failed some other step. The default is ``is_valid==True`` where the assumption is that you don't want to execute (i.e., short circuit) if an item has failed some previous step.