     */
    public function setDestinationKey(?int $destinationKey = null): self
    {
        // validation for constraint: int
        if (!is_null($destinationKey) && !(is_int($destinationKey) || ctype_digit($destinationKey))) {
            throw new InvalidArgumentException(sprintf('Invalid value %s, please provide an integer value, %s given', var_export($destinationKey, true), gettype($destinationKey)), __LINE__);
        }
        $this->destinationKey = $destinationKey;
        
        return $this;
    }
}