- @rtype: tuple; (list, list)
- @return: Tuple containing a list of node names on which the hook
- should run before the execution and a list of node names on which the
- hook should run after the execution. No nodes should be returned as an
- empty list (and not None).
+ @rtype: tuple; (list, list) or (list, list, list)
+ @return: Tuple containing a list of node UUIDs on which the hook
+ should run before the execution and a list of node UUIDs on which the
+ hook should run after the execution. As it might be possible that the
+ node UUID is not known at the time this method is invoked, an optional
+ third list can be added which contains node names on which the hook
+ should run after the execution (in case of node add, for instance).
+ No nodes should be returned as an empty list (and not None).