How to use the lottie.exporters.gif._png_gif_prepare function in lottie

MIT (Unified Message Relay)
        AGPL 3.0 (Python Lottie)
    """
    # Import only upon calling the method due to added binary dependencies
    # (libcairo)
    from lottie.exporters.cairo import export_png
    from lottie.exporters.gif import _png_gif_prepare

    start = int(animation.in_point)
    end = int(animation.out_point)
    frames = []
    for i in range(start, end+1, skip_frames):
        file = BytesIO()
        export_png(animation, file, i, dpi)
        file.seek(0)
        frames.append(_png_gif_prepare(Image.open(file)))

    duration = 1000 / animation.frame_rate * (1 + skip_frames) / 2
    frames[0].save(
        fp,
        format='GIF',
        append_images=frames[1:],
        save_all=True,
        duration=duration,
        loop=0,
        transparency=255,
        disposal=2,
    )