Cart/Entity/CartItem.php
protected function assertItemAdjustmentClass(Common\AdjustmentInterface $adjustment)
    {
        if (!$adjustment instanceof Model\CartItemAdjustmentInterface) {
            throw new InvalidArgumentException("Expected instance of " . Model\CartItemAdjustmentInterface::class);
        }
    }
protected function assertItemAdjustmentClass(Common\AdjustmentInterface $adjustment)
    {
        if (!$adjustment instanceof Model\CartItemAdjustmentInterface) {
            throw new InvalidArgumentException("Expected instance of " . Model\CartItemAdjustmentInterface::class);
        }
    }
Asserts that the given adjustment is an instance of the expected class.

@param Common\AdjustmentInterface $adjustment