LastName::processAfterSave

public function processAfterSave(Item $itemBeforeSave, Item $item, Context $context = null): FieldAfterSaveResult
{
	$result = new FieldAfterSaveResult();

	$defaultLastName = $item->getTitlePlaceholder();
	if ($itemBeforeSave->isNew() && $this->isNameAndLastNameEmpty($item) && !empty($defaultLastName))
	{
		$result->setNewValue($this->getName(), $defaultLastName);
	}

	return $result;
}