code: private ZooPC checkObjectForRefresh(Object pc) {
          if (!(pc instanceof ZooPC)) {
          	throw DBLogger.newUser("The object is not persistent capable: " + pc.getClass());
          }
          
          ZooPC pci = (ZooPC) pc;
          if (!pci.jdoZooIsPersistent()) {
          	return pci;
          }
  
          if (pci.jdoZooGetContext().getSession() != this) {
          	throw DBLogger.newUser("The object belongs to a different PersistenceManager.");
          }
          return pci;
  	}
docs: For refresh, we can ignore things like deletion or transience.
  @param pc
  @return the refreshed object