def METHOD_NAME(section: Ann[Optional[str], Arg(show_default='all sections')] = None):
    '''Lists every config variable in the section.'''
    from hailtop.config import get_user_config  # pylint: disable=import-outside-toplevel
    config = get_user_config()
    if section:
        for key, value in config.items(section):
            print(f'{key}={value}')
    else:
        for sname, items in config.items():
            for key, value in items.items():
                print(f'{sname}/{key}={value}')