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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

async def updateconfig(self):
        "Reload configurations, remove non-exist servers, add new servers, and leave others unchanged"
        exists = {}
        for s in self.connections:
            exists[(s.protocol.vhost, s.rawurl)] = s
        self._createServers(self, '', exists = exists)
        for _,v in exists.items():
            await v.shutdown()
            self.connections.remove(v)