@audio_video_fx
def volumex(clip, factor):
 return clip.fl((lambda gf, t: (factor * gf(t))), keep_duration=True)

@ audio_video_fx def volumex ( clip , factor ) : return clip . fl ( ( lambda gf , t : ( factor * gf ( t ) ) ) , keep_duration = True )
returns a clip with audio volume multiplied by the value factor .