fi furnace: version for first tests

Change-Id: I841bc9dab210bfc907d2ae56c42198c30df9a3a4

frappy/ctrlby.py

@@ -143,6 +143,9 @@ class HasControlledBy(WrapControlledBy):
         # is before HasControlledBy in the method resolution order
         return self.set_target(value)
 
+    def set_off(self):
+        """typically needs to be overridden"""
+
 
 class HasOutputModule:
     """mixin for modules having an output module