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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 serverless(self):
 """ Access the Serverless Twilio Domain :returns: Serverless Twilio Domain :rtype: twilio.rest.serverless.Serverless """

        if self._serverless is None:
            from twilio.rest.serverless import Serverless
            self._serverless = Serverless(self)
        return self._serverless