def _change_volume(self, step=None, value=None):
if step is not None:
volume = sound.get_volume() + step
elif value is not None:
volume = value
volume = min(max(0, volume), _VOLUME_MAX)
sound.set_volume(volume)
sound.set_muted(volume == 0)
def handle_volume_mute(self, event_time):
if sound.get_muted() is True:
sound.set_muted(False)
else:
sound.set_muted(True)
