code: def get_cached_output(self, placeholder_name, instance):
          
          cachekey = self.get_output_cache_key(placeholder_name, instance)
          return cache.get(cachekey)
docs: .. versionadded:: 0.9
             Return the cached output for a rendered item, or ``None`` if no output is cached.
  
             This method can be overwritten to implement custom caching mechanisms.
             By default, this function generates the cache key using :func:`get_output_cache_key`
             and retrieves the results from the configured Django cache backend (e.g. memcached).