def METHOD_NAME(self):
    """
    Clears the cache and gets its latest version, not Thread safe !
    Acquire a lock before using it ! ( and release it afterwards ! )
    """
    self.__rssCache.purgeAll()
    if self.__updateFunc is None:
        return S_ERROR("RSSCache has no updateFunction")
    newCache = self.__updateFunc()
    if not newCache["OK"]:
        return newCache
    itemsAdded = self.__updateCache(newCache["Value"])
    return itemsAdded