docs: def copy_object(self, container, obj, metadata=None,
                      destination=None, **kwargs):
          """Copy object
  
          :param container: container name (Container is equivalent to
                            Bucket term in Amazon).
          :param obj: object name (Object is equivalent to
                      Key term in Amazon).
          :param destination: The container and object name of the destination
                              object in the form of /container/object; if None,
                              the copy will use the source as the destination.
          :param metadata(dict): additional metadata(headers)
                                 to include in the request
          :param **kwargs(dict): extend args for specific driver.
          """
          try:
              LOG.debug('copy_object() with %s is success.', self.driver)
              return self.driver.copy_object(container, obj, metadata=metadata,
                                             destination=destination, **kwargs)
          except DriverException as e:
              LOG.exception('copy_object() with %s raised\
                              an exception %s.', self.driver, e)