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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 _discover_mac(self):
 """ Discovers MAC address of device. Discovery is done by sending a UDP broadcast. All configured devices reply. The response contains the MAC address in both needed formats. Discovery of multiple switches must be done synchronously. :returns: Tuple of MAC address and reversed MAC address. """

        mac = None
        mac_reversed = None
        cmd = MAGIC + DISCOVERY
        resp = self._udp_transact(cmd, self._discovery_resp,
                                  broadcast=True,
                                  timeout=DISCOVERY_TIMEOUT)
        if resp:
            (mac, mac_reversed) = resp
        if mac is None:
            raise S20Exception("Couldn't discover {}".format(self.host))
        return (mac, mac_reversed)