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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 _verifyHostKey(self, hostKey, fingerprint):
 """Called when ssh transport requests us to verify a given host key. Return a deferred that callback if we accept the key or errback if we decide to reject it. """

        if fingerprint in self.knownHosts:
            return defer.succeed(True)
        return defer.fail(UnknownHostKey(hostKey, fingerprint))