def _from_inventory(self, inventory):
        """
        Transforms the inventory from Django's content types to FeinCMS's
        ContentProxy counts format.
        """

        tmap = self._translation_map()

        return {
            region: [(pk, tmap[-ct]) for pk, ct in items]
            for region, items in inventory.items()
            if region != "_version_"
        }

        Transforms the inventory from Django's content types to FeinCMS's
        ContentProxy counts format.
        
feincms/extensions/ct_tracker.py