Build an argument parser using optparse. Use it when python version is 2.5 or 2.6.

def build_arg_parser2():
    """
    Build an argument parser using optparse. Use it when python version is 2.5 or 2.6.

    """
    usage_str = "Smatch table calculator -- arguments"
    parser = optparse.OptionParser(usage=usage_str)
    parser.add_option("--fl", dest="fl", type="string", help='AMR ID list file')
    parser.add_option("-f", dest="f", type="string", action="callback", callback=cb, help="AMR IDs (at least one)")
    parser.add_option("-p", dest="p", type="string", action="callback", callback=cb, help="User list")
    parser.add_option("--fd", dest="fd", type="string", help="file directory")
    parser.add_option("-r", "--restart", dest="r", type="int", help='Restart number (Default: 4)')
    parser.add_option("-v", "--verbose", action='store_true', dest="v", help='Verbose output (Default:False)')
    parser.set_defaults(r=4, v=False, ms=False, fd=isi_dir_pre)
    return parser