code: def _GetSerializedAttributeContainerByIndex(self, container_type, index):
      
      container_list = self._GetSerializedAttributeContainerList(container_type)
      return container_list.GetAttributeContainerByIndex(index)
docs: Retrieves a specific serialized attribute container.
  
      Args:
        container_type (str): attribute container type.
        index (int): attribute container index.
  
      Returns:
        bytes: serialized attribute container data or None if not available.