TYPO3: Access old-style piBase methods from Extbase extension

TYPO3: Access old-style piBase methods from Extbase extension

Can I access old-style piBase classes and methods from my Extbase extension?
For example, can I create an AccessMyoldExtensionService.php Service as a
wrapper class and then pull the return values into my controller?
In my case, I need to return a list of old data records that can't be
migrated to MVC style directly.
If so, what would the basic approach be?