public function setShowHide($showHide)
    {
        if (in_array($showHide, ShowHide::asArray()) === true) {
            $this->showHide = $showHide;
        } else {
            $msg = "The 'showHide' argument must be a value from the ShowHide enumeration.";
            throw new InvalidArgumentException($msg);
        }
    }