Nette\PhpGenerator\Property::setVisibility PHP Method

    public function setVisibility($val)
    {
        if (!in_array($val, ['public', 'protected', 'private'], TRUE)) {
            throw new Nette\InvalidArgumentException('Argument must be public|protected|private.');
        }
        $this->visibility = (string) $val;
        return $this;
    }