def check(self, defn, msg=None):
        """Uses the definitions slice() method to determine its start/stop
        range.
        """
        # Check enum does not contain boolean keys
        if (defn.slice().start != self.prevstop):
            self.messages.append(self.msg % str(defn.name))
            # TODO self.messages.append("TBD location message")
            self.valid = False

        self.prevstop = defn.slice().stop
Uses the definitions slice() method to determine its start/stop
        range.