Data to send to do a lastError.

def __last_error(namespace, args):
    """Data to send to do a lastError.
    """
    cmd = SON([("getlasterror", 1)])
    cmd.update(args)
    splitns = namespace.split('.', 1)
    return query(0, splitns[0] + '.$cmd', 0, -1, cmd,
                 None, DEFAULT_CODEC_OPTIONS)