public function __construct($label = NULL, $multiple = FALSE)
{
parent::__construct($label);
$this->control->type = 'file';
$this->control->multiple = (bool) $multiple;
$this->setOption('type', 'file');
$this->addCondition(Forms\Form::FILLED)->addRule([$this, 'isOk'], Forms\Validator::$messages[self::VALID]);
}