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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 _get_firmware_update_element(self):
 """Get the url for firmware update :returns: firmware update url :raises: Missing resource error on missing url """

        fw_update_action = self._actions.update_firmware
        if not fw_update_action:
            raise (sushy.exceptions.
                   MissingActionError(action='#UpdateService.SimpleUpdate',
                                      resource=self._path))
        return fw_update_action