/** Adds a responder to an Array of responders. */
public function addResponder(responder:IResponder):void {
	if(responder == null) return;
	for each(var responderInList:IResponder in _responders) {
		if(responderInList == responder) return;
	}
	_responders.push(responder);
}

/** Removes a responder from an Array of responders. */
public function removeResponder(responder:IResponder):void {
	if(responder == null) return;
	for(var i:int=0; i < _responders.length; i++) {
		if(_responders[i] == responder) {
			_responders = _responders.splice(i, 1);
		}
	}
}

Add & Remove to Array

list, array

ActionScript 3