code: def _currentlyValidAsReferentFor(self, store):
          
          if store is None:
              # If your store is None, you can refer to whoever you want.  I'm in
              # a store but it doesn't matter that you're not.
              return True
          if self.store is not store:
              return False
          if self.__deletingObject:
              return False
          return True
docs: Is this object currently valid as a reference?  Objects which will be
          deleted in this transaction, or objects which are not in the same store
          are not valid.  See attributes.reference.__get__.