def _destroy(self):
        """Destruction code to decrement counters"""
        self.unuse_region()

        if self._rlist is not None:
            # Actual client count, which doesn't include the reference kept by the manager, nor ours
            # as we are about to be deleted
            try:
                if len(self._rlist) == 0:
                    # Free all resources associated with the mapped file
                    self._manager._fdict.pop(self._rlist.path_or_fd())
                # END remove regions list from manager
            except (TypeError, KeyError):
                # sometimes, during shutdown, getrefcount is None. Its possible
                # to re-import it, however, its probably better to just ignore
                # this python problem (for now).
                # The next step is to get rid of the error prone getrefcount alltogether.
                pass
Destruction code to decrement counters