code: def _fetch(self):
          
          if not self.is_local and not self._obcache_current:
              #print('fetching data from %s' % self._ref.id)
              def _remote_fetch(id):
                  return distob.engine[id]
              self._obcache = self._dv.apply_sync(_remote_fetch, self._id)
              self._obcache_current = True
              self.__engine_affinity__ = (distob.engine.eid, 
                                          self.__engine_affinity__[1])
docs: forces update of a local cached copy of the real object
          (regardless of the preference setting self.cache)