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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:
 def prep_connection(self, creds=None, keyspace=None, node_auto_discovery=True):
 """ Do login and set_keyspace tasks as necessary, and also check this node's idea of the Cassandra ring. Expects that our connection is alive. Return a Deferred that will fire with the ring information, or be errbacked if something goes wrong. """


        d = defer.succeed(None)

        if creds is not None:
            d.addCallback(lambda _: self.my_login(creds))
        if keyspace is not None:
            d.addCallback(lambda _: self.my_set_keyspace(keyspace))
        if node_auto_discovery:
            d.addCallback(lambda _: self.my_describe_ring(keyspace))

        return d