Rasa Feedback Form Dynamic Slot Implementation

Hi am trying to implement feedback from the user in rasa 1.10. Using forms If the user feedback is less than 3 bot will ask for feedback comments. If user feedback is greater than 3 bot will end with thank you note.

How can I capture the dynamic slot of free text if get the rating less than 3 in validation method user comments Below is snippet @Juste

FormGetRating(FormAction): “”" Feedback Rating “”"

def name(self) -> Text:
    """Unique identifier of the form"""
    return "feedback_form"

def required_slots(tracker: Tracker) -> List[Text]:
    """A list of required slots that the form has to fill"""
    return ["rating"]

def slot_mappings(self) -> Dict[Text, Union[Dict, List[Dict]]]:
    """A dictionary to map required slots to
        - an extracted entity
        - intent: value pairs
        - a whole message
        or a list of them, where a first match will be picked"""
    return {
        "rating": [

def validate_rating(self,
                    value: Text,
                    dispatcher: CollectingDispatcher,
                    tracker: Tracker,
                    domain: Dict[Text, Any],
                    ) -> Dict[Text, Any]:

    if value != None:
        rating = int(value)
        logger.info("User rating : {}".format(rating))
    if (1 <= rating < 3):
    elif(3 <= rating <= 5):

    return {"rating": rating}

def submit(self, dispatcher: CollectingDispatcher, tracker: Tracker,
           domain: Dict[Text, Any],) -> List[Dict]:
    """Define what the form has to do
        after all required slots are filled"""
    return []