def apply_to_audio(func, clip, *args, **kwargs):
    """Applies the function ``func`` to the audio of the clip created with ``func``."""
    new_clip = func(clip, *args, **kwargs)
    if getattr(new_clip, "audio", None):
        new_clip.audio = func(new_clip.audio, *args, **kwargs)
    return new_clip
Applies the function ``func`` to the audio of the clip created with ``func``.
moviepy/decorators.py