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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def insertion(args):
 """ %prog insertion mic.mac.bed Find IES based on mapping MIC reads to MAC genome. Output a bedfile with 'lesions' (stack of broken reads) in the MAC genome. """

    p = OptionParser(insertion.__doc__)
    p.add_option("--mindepth", default=6, type="int",
                 help="Minimum depth to call an insertion")
    p.set_outfile()
    opts, args = p.parse_args(args)

    if len(args) != 1:
        sys.exit(not p.print_help())

    bedfile, = args
    mindepth = opts.mindepth
    bed = Bed(bedfile)
    fw = must_open(opts.outfile, "w")
    for seqid, feats in bed.sub_beds():
        left_ends = Counter([x.start for x in feats])
        right_ends = Counter([x.end for x in feats])
        selected = []
        for le, count in left_ends.items():
            if count >= mindepth:
                selected.append((seqid, le, "LE-{0}".format(le), count))
        for re, count in right_ends.items():
            if count >= mindepth:
                selected.append((seqid, re, "RE-{0}".format(re), count))
        selected.sort()
        for seqid, pos, label, count in selected:
            label = "{0}-r{1}".format(label, count)
            print("\t".join((seqid, str(pos - 1), str(pos), label)), file=fw)