code: def create_group_dampening(self, group_id, dampening):
          
          data = self._serialize_object(dampening)
          url = self._service_url(['triggers', 'groups', group_id, 'dampenings'])
          return Dampening(self._post(url, data))
docs: Create a new group dampening
  
          :param group_id: Group Trigger id attached to dampening
          :param dampening: Dampening definition to be created.
          :type dampening: Dampening
          :return: Group Dampening created