@staticmethod
def get_tables(sheets):
    tables = {}
    root_tables = []
    for sheet in sheets:
        if (sheet.name[0] == IGNORE_WILDCARD):
            continue
        table = Table(sheet)
        tables[table.name] = table
        if table.is_root:
            root_tables.append(table)
    if (len(root_tables) == 1):
        return (root_tables[0], tables)
    else:
        raise Exception('Root table must be one')
        sys.exit()
@staticmethod
def get_tables(sheets):
    tables = {}
    root_tables = []
    for sheet in sheets:
        if (sheet.name[0] == IGNORE_WILDCARD):
            continue
        table = Table(sheet)
        tables[table.name] = table
        if table.is_root:
            root_tables.append(table)
    if (len(root_tables) == 1):
        return (root_tables[0], tables)
    else:
        raise Exception('Root table must be one')
        sys.exit()