docs: def stat_object(self, container, obj):
          """Stat object metadata
  
          :param container: container name (Container is equivalent to
                            Bucket term in Amazon).
          :param obj: object name (Object is equivalent to
                      Key term in Amazon).
          """
          LOG.debug('stat_object() with %s is success.', self.driver)
          return self.driver.stat_object(container, obj)