Explicit exit from a form

I have been trying to find all the possible ways to exit explicitly from a form after a certain condition is met. But no matter how many times i try i am not able to do it. I am using RASA OPEN SOURCE

    def validate_item_name(
        self, value: Text, dispatcher: CollectingDispatcher, tracker: Tracker, domain: DomainDict
        ):
        if value.lower() in existing_items:
            text = get_text_from_lang(
                tracker,
                ['This item already exists in the inventory. Abandoning action, consider updating it instead.',
                'यह आइटम पहले से ही इन्वेंटरी में मौजूद है। इसे अपडेट करने पर विचार करें।']
            )
            dispatcher.utter_message(text=text)
            return {"item_name": None, "cancel_add": "true"}
        
        return [SlotSet("item_name", value)]
  - rule: Cancel add item form
    condition:
      - active_loop: additem_form
      - slot_was_set:
          - cancel_add: true
    steps:
      - action: action_deactivateadd_loop
      - active_loop: null
class ActionDeactivateAddLoop(Action):
    def name(self) -> str:
        return "action_deactivateadd_loop"
    
    def run(self,dispatcher, tracker :Tracker, domain:Dict) -> List[Dict]:
        cond = tracker.get_slot("cancel_add")
        if cond == "true":
            return [ActiveLoop(None),AllSlotsReset()]
        else:
            return []

This is how tried to implement it but it sill didn’t work