code: def loaded(self, oself, dbval):
          
          setattr(oself, self.dbunderlying, dbval)
          delattr(oself, self.underlying)
docs: This method is invoked when the item is loaded from the database, and
          when a transaction is reverted which restores this attribute's value.
  
          @param oself: an instance of an item which has this attribute.
  
          @param dbval: the underlying database value which was retrieved.