def checkAndSet(self, key, val, cas, flags=0, expireTime=0):
        return self._set("cas", key, val, flags, expireTime, cas)
Change the content of C{key} only if the C{cas} value matches the
dataset/ETHPy150Open kuri65536/python-for-android/python-modules/twisted/twisted/protocols/memcache.py/MemCacheProtocol.checkAndSet