code: def _cleanup(self):
          '''
          Cleanup all the local data.
          '''
          self._select_cb = None
          self._commit_cb = None
          self._rollback_cb = None
          super(TransactionClass, self)._cleanup(f _cleanup(self):
          '''
          Cleanup all the local data.
          '''
          self._select_cb = None
          self._commit_cb = None
          self._rollback_cb = None
          super(TransactionClass, self)._cleanup()
docs: Cleanup all the local data.