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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 machine_to_machine(self):
 """ Access the machine_to_machine :returns: twilio.rest.api.v2010.account.available_phone_number.machine_to_machine.MachineToMachineList :rtype: twilio.rest.api.v2010.account.available_phone_number.machine_to_machine.MachineToMachineList """

        if self._machine_to_machine is None:
            self._machine_to_machine = MachineToMachineList(
                self._version,
                account_sid=self._solution['account_sid'],
                country_code=self._solution['country_code'],
            )
        return self._machine_to_machine