function setServerTag($key, $value, $multicall = false)
    {
        if (!is_string($key)) {
            throw new InvalidArgumentException('key = ' . print_r($key, true));
        }
        if (!is_string($value)) {
            throw new InvalidArgumentException('value = ' . print_r($value, true));
        }

        return $this->execute(ucfirst(__FUNCTION__), array($key, $value), $multicall);
    }