Assert\Assertion::ipv4 PHP 메소드

    public static function ipv4($value, $flag = null, $message = null, $propertyPath = null)
    {
        self::ip($value, $flag | FILTER_FLAG_IPV4, $message ?: 'Value "%s" was expected to be a valid IPv4 address.', $propertyPath);
        return true;
    }