def _convert_to_bool(argument):
    lowered = argument.lower()
    if lowered in ('yes', 'y', 'true', 't', '1', 'enable', 'on'):
        return True
    elif lowered in ('no', 'n', 'false', 'f', '0', 'disable', 'off'):
        return False
    else:
        raise BadArgument(lowered + ' is not a recognised boolean option')