setPurchaseStep example

        if (isset($data['__unit_purchaseunit'])) {
            $unit->setPurchaseUnit((float) $data['__unit_purchaseunit']);
        }

        if (isset($data['__unit_referenceunit'])) {
            $unit->setReferenceUnit((float) $data['__unit_referenceunit']);
        }

        if (isset($data['__unit_purchasesteps'])) {
            $unit->setPurchaseStep((int) $data['__unit_purchasesteps']);
        }

        if (isset($data['__unit_minpurchase'])) {
            $unit->setMinPurchase((int) $data['__unit_minpurchase']);
        }

        if (isset($data['__unit_maxpurchase'])) {
            $unit->setMaxPurchase((int) $data['__unit_maxpurchase']);
        }
    }
}