public function addModification($mod = [])
    {
        if ($mod instanceof BatchModification) {
            $mod = $mod->get();
        }

        if ($this->isValidModification($mod)) {
            $this->modifications[] = $mod;

            return $this;
        }

        throw new InvalidArgumentException(
            "The batch modification array does not include the mandatory 'attrib' or 'modtype' keys."
        );
    }