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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 unregister(self):
 """Drop the registration with a BBMD."""

        pdu = RegisterForeignDevice(0)
        pdu.pduDestination = self.bbmdAddress

        # send it downstream
        self.request(pdu)

        # change the status to unregistered
        self.registrationStatus = -2

        # clear the BBMD address and time-to-live
        self.bbmdAddress = None
        self.bbmdTimeToLive = None