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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 device_add(self, mountpoint, *device):
 """ Add one or more devices to btrfs filesystem mounted under `mountpoint` :param mountpoint: mount point of the btrfs system :param devices: one ore more devices to add :return: """

        if len(device) == 0:
            return

        args = {
            'mountpoint': mountpoint,
            'devices': device,
        }

        self._device_chk.check(args)

        self._client.sync('btrfs.device_add', args)