code: def get_storage(obj):
      
      annotation = IAnnotations(obj)
      if annotation.get(SNAPSHOT_STORAGE) is None:
          annotation[SNAPSHOT_STORAGE] = PersistentList()
      return annotation[SNAPSHOT_STORAGE]
docs: Get or create the audit log storage for the given object
  
      :param obj: Content object
      :returns: PersistentList