How should stories be if an action sets a slot only sometimes?

In the docs Slots says that if an action sets a slot this should be included in the stories. However, if an action sets a slot under some circumstances, for example if the action was reading a list based on a counter and now it reached the end so it need to reset the counter, should we include the stories for both cases? one where the the action doesn’t set a slot and one where it sets it to zero.

If so, I did it but I still get this error “UserWarning: Action ‘action_test’ set a slot type ‘cnt’ which it never set during the training. This can throw off the prediction. Make sure to include training examples in your stories for the different types of slots this action can return. Remember: you need to set the slots manually in the stories by adding ‘- slot{“cnt”: 0}’ after the action.”