<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def error(args):
 """ %prog error version backup_folder Find all errors in ../5-consensus/*.err and pull the error unitigs into backup/ folder. """

    p = OptionParser(error.__doc__)
    opts, args = p.parse_args(args)

    if len(args) != 2:
        sys.exit(not p.print_help())

    version, backup_folder = args
    mkdir(backup_folder)

    fw = open("errors.log", "w")

    seen = set()
    for g in glob("../5-consensus/*.err"):
        if "partitioned" in g:
            continue

        fp = open(g)
        partID = op.basename(g).rsplit(".err", 1)[0]
        partID = int(partID.split("_")[-1])

        for row in fp:
            if row.startswith(working):
                unitigID = row.split("(")[0].split()[-1]
                continue

            if not failed.upper() in row.upper():
                continue

            uu = (version, partID, unitigID)
            if uu in seen:
                continue
            seen.add(uu)

            print("\t".join(str(x) for x in (partID, unitigID)), file=fw)

            s = [str(x) for x in uu]
            unitigfile = pull(s)
            cmd = "mv {0} {1}".format(unitigfile, backup_folder)
            sh(cmd)

        fp.close()

    logging.debug("A total of {0} unitigs saved to {1}.".\
                 format(len(seen), backup_folder))