public function addPClass($pclass)
    {
        if (! $pclass instanceof KlarnaPClass) {
            throw new Klarna_InvalidTypeException('pclass', 'KlarnaPClass');
        }

        if (!isset($this->pclasses) || !is_array($this->pclasses)) {
            $this->pclasses = array();
        }

        if ($pclass->getDescription() === null || $pclass->getType() === null) {
            //Something went wrong, do not save these!
            return;
        }

        if (!isset($this->pclasses[$pclass->getEid()])) {
            $this->pclasses[$pclass->getEid()] = array();
        }
        $this->pclasses[$pclass->getEid()][$pclass->getId()] = $pclass;
    }