BasketItemBase::getCallbackFunction

public function getCallbackFunction()
{
	$callbackFunction = $this->getField('CALLBACK_FUNC');
	if (empty($callbackFunction))
	{
		return null;
	}

	$callbackFunction = trim((string)$callbackFunction);
	if (empty($callbackFunction) || !function_exists($callbackFunction))
	{
		return null;
	}

	return $callbackFunction;
}