code: public function beforeAction($action)
  	{
  		$user = Yii::$app->getUser();
  
  		$controller = $action->controller;
  
  		if ($controller->module !== null) {
  			if ($user->checkAccess($this->getItemName($controller->module) . $this->separator . '*', $this->params)) {
  				return true;
  			}
  		}
  
  		if ($user->checkAccess($this->getItemName($controller) . $this->separator . '*', $this->params)) {
  			return true;
  		}
  
  		if ($user->checkAccess($itemName = $this->getItemName($action), $this->params)) {
  			return true;
  		}
  
  		if (isset($this->denyCallback)) {
  			call_user_func($this->denyCallback, $itemName, $action);
  		} else {
  			$this->denyAccess($user);
  		}
  		return false;
  	}
docs: This method is invoked right before an action is to be executed (after all possible filters.)
  You may override this method to do last-minute preparation for the action.
  
  @param Action $action the action to be executed.
  @return boolean whether the action should continue to be executed.