def shutdown(self):
        self._shuttingDown = {key: Deferred()
                              for key in self.cachedConnections.keys()}
        return DeferredList(
            [maybeDeferred(p.transport.loseConnection)
             for p in self.cachedConnections.values()]
             + self._shuttingDown.values())
batch filter should accept missing data with None in the measurements
dataset/ETHPy150Open twisted/vertex/vertex/conncache.py/ConnectionCache.shutdown--crossover with--dataset/ETHPy150Open rlabbe/filterpy/filterpy/kalman/tests/test_ukf.py/test_batch_missing_data