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

def grid_desired_size(
        grid,
        media_info,
        width=Config.contact_sheet_width,
        horizontal_margin=Config.grid_horizontal_spacing):
    """Computes the size of the images placed on a mxn grid with given fixed width.
    Returns (width, height)
    """
    desired_width = (width - (grid.x - 1) * horizontal_margin) / grid.x
    desired_width = int(math.floor(desired_width))

    return media_info.desired_size(width=desired_width)

help="do not capture frames in the first and last n percent of total time",
        dest="delay_percent",
        type=int,
        default=Config.delay_percent)
    parser.add_argument(
        "--grid-spacing",
        help="number of pixels spacing captures both vertically and horizontally",
        dest="grid_spacing",
        type=int,
        default=Config.grid_spacing)
    parser.add_argument(
        "--grid-horizontal-spacing",
        help="number of pixels spacing captures horizontally",
        dest="grid_horizontal_spacing",
        type=int,
        default=Config.grid_horizontal_spacing)
    parser.add_argument(
        "--grid-vertical-spacing",
        help="number of pixels spacing captures vertically",
        dest="grid_vertical_spacing",
        type=int,
        default=Config.grid_vertical_spacing)
    parser.add_argument(
        "-w", "--width",
        help="width of the generated contact sheet",
        dest="vcs_width",
        type=int,
        default=Config.contact_sheet_width)
    parser.add_argument(
        "-g", "--grid",
        help="display frames on a mxn grid (for example 4x5). The special value zero (as in 2x0 or 0x5 or 0x0) is only allowed when combined with --interval or with --manual. Zero means that the component should be automatically deduced based on other arguments passed.",
        dest="grid",