def connectionLostForKey(self, key):
        if key in self.cachedConnections:
            del self.cachedConnections[key]
        if self._shuttingDown and self._shuttingDown.get(key):
            d, self._shuttingDown[key] = self._shuttingDown[key], None
            d.callback(None)
Remove lost connection from cache.
dataset/ETHPy150Open twisted/vertex/vertex/conncache.py/ConnectionCache.connectionLostForKey