code: def trigger(self_, *param_names):
          
          events = self_.self_or_cls.param._events
          watchers = self_.self_or_cls.param._watchers
          self_.self_or_cls.param._events  = []
          self_.self_or_cls.param._watchers = []
          param_values = dict(self_.get_param_values())
          params = {name: param_values[name] for name in param_names}
          self_.self_or_cls.param._TRIGGER = True
          self_.set_param(**params)
          self_.self_or_cls.param._TRIGGER = False
          self_.self_or_cls.param._events = events
          self_.self_or_cls.param._watchers = watchers
docs: Trigger watchers for the given set of parameter names. Watchers
          will be triggered whether or not the parameter values have
          actually changed.