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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 UNREACH(self):
 """ Returns true if the device or any children is not reachable """

        if self._VALUES.get(PARAM_UNREACH, False):
            return True
        else:
            for device in self._hmchannels.values():
                if device.UNREACH:
                    return True
        return False