How to use the vcsi.vcsi.Config.capture_alpha function in vcsi

dest="recursive")
    parser.add_argument(
        "--timestamp-border-mode",
        action="store_true",
        help="Draw timestamp text with a border instead of the default rectangle.",
        dest="timestamp_border_mode")
    parser.add_argument(
        "--timestamp-border-size",
        type=int,
        default=Config.timestamp_border_size,
        help="Size of the timestamp border in pixels (used only with --timestamp-border-mode).",
        dest="timestamp_border_size")
    parser.add_argument(
        "--capture-alpha",
        type=int,
        default=Config.capture_alpha,
        help="Alpha channel value for the captures (transparency in range [0, 255]). Defaults to 255 (opaque)",
        dest="capture_alpha")
    parser.add_argument(
        "--version",
        action="version",
        version="%(prog)s version {version}".format(version=__version__))
    parser.add_argument(
        "--list-template-attributes",
        action="store_true",
        dest="list_template_attributes")
    parser.add_argument(
        "--frame-type",
        type=str,
        default=DEFAULT_FRAME_TYPE,
        help="Frame type passed to ffmpeg 'select=eq(pict_type,FRAME_TYPE)' filter. Should be one of ('I', 'B', 'P') or the special type 'key' which will use the 'select=key' filter instead.",
        dest="frame_type")