code: def _get_manifest_list(self, image):
          
          if image in self.manifest_list_cache:
              return self.manifest_list_cache[image]
  
          manifest_list = get_manifest_list(image, image.registry,
                                            insecure=self.parent_registry_insecure,
                                            dockercfg_path=self.parent_registry_dockercfg_path)
          if '@sha256:' in str(image) and not manifest_list:
              # we want to adjust the tag only for manifest list fetching
              image = image.copy()
  
              try:
                  config_blob = get_config_from_registry(
                      image, image.registry, image.tag, insecure=self.parent_registry_insecure,
                      dockercfg_path=self.parent_registry_dockercfg_path
                  )
              except (HTTPError, RetryError, Timeout) as ex:
                  self.log.warning('Unable to fetch config for %s, got error %s',
                                   image, ex.response.status_code)
                  raise RuntimeError('Unable to fetch config for base image')
  
              release = config_blob['config']['Labels']['release']
              version = config_blob['config']['Labels']['version']
              docker_tag = "%s-%s" % (version, release)
              image.tag = docker_tag
  
              manifest_list = get_manifest_list(image, image.registry,
                                                insecure=self.parent_registry_insecure,
                                                dockercfg_path=self.parent_registry_dockercfg_path)
          self.manifest_list_cache[image] = manifest_list
          return self.manifest_list_cache[image]
docs: try to figure out manifest list