src/Plugin.php
private function secondParamValidation(Event $event)
    {
        $params = $event->getCustomParams();
        return (!isset($params[1]) || (is_numeric($params[1]) && $params[1] >= 1 && $params[1] <= $this->maxDieSides));
    }
private function secondParamValidation(Event $event)
    {
        $params = $event->getCustomParams();
        return (!isset($params[1]) || (is_numeric($params[1]) && $params[1] >= 1 && $params[1] <= $this->maxDieSides));
    }
Verify parameter 2 is valid

@param Event $event
@return bool