(default 2).
* `--device DEVICE` : select another sound device.
* `--list-devices` : list available sound devices.
+ * `--load-all-musics` : load all the music when starting (default True)
* `-- ARGS` : arguments for Kivy library.
## Configure keys
* `command: my_command` : Gives the command to run.
* `wait: true/false` (optional, default false) if true, waits for the
command to finish (this wait is not interruptible by interrupt_wait)
+- `load_music/unload_music` : load/unload a music from memory. Useful
+ with `load_all_musics` option only
+ * `music: "music.mp3" the music to load/unload
### `aliases` : define aliases