code: def setPrivates(self, fieldDict) :
          
          
          for priv in self.privates :
              if priv in fieldDict :
                  setattr(self, priv, fieldDict[priv])
              else :
                  setattr(self, priv, None)
          
          if self._id is not None :
              self.URL = "%s/%s" % (self.documentsURL, self._id)
docs: will set self._id, self._rev and self._key field.