How to use the flattentool.lib.parse_sheet_configuration function in flattentool

if input_format is None:
        raise Exception("You must specify an input format (may autodetect in future")
    elif input_format not in INPUT_FORMATS:
        raise Exception("The requested format is not available")
    if metatab_name and base_json:
        raise Exception("Not allowed to use base_json with metatab")

    if root_is_list:
        base = None
    elif base_json:
        with open(base_json) as fp:
            base = json.load(fp, object_pairs_hook=OrderedDict)
    else:
        base = OrderedDict()

    base_configuration = parse_sheet_configuration(
        [item.strip() for item in default_configuration.split(",")]
    )

    cell_source_map_data = OrderedDict()
    heading_source_map_data = OrderedDict()

    if metatab_name and not root_is_list:
        spreadsheet_input_class = INPUT_FORMATS[input_format]
        spreadsheet_input = spreadsheet_input_class(
            input_name=input_name,
            timezone_name=timezone_name,
            root_list_path="meta",
            include_sheets=[metatab_name],
            convert_titles=convert_titles,
            vertical_orientation=metatab_vertical_orientation,
            id_name=id_name,

def configure_sheets(self):
        for sub_sheet_name in self.sub_sheet_names:
            self.sheet_configuration[sub_sheet_name] = parse_sheet_configuration(
                self.get_sheet_configuration(sub_sheet_name)
            )