mpyw\Co\Internal\CoOption::validateNaturalInt PHP Метод

    private static function validateNaturalInt($key, $value)
    {
        $value = filter_var($value, FILTER_VALIDATE_INT);
        if ($value === false) {
            throw new \InvalidArgumentException("Option[{$key}] must be integer.");
        }
        if ($value < 0) {
            throw new \DomainException("Option[{$key}] must be positive or zero.");
        }
        return $value;
    }