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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 _install_kraken_db(datadir, args):
 """Install kraken minimal DB in genome folder. """

    import requests
    kraken = os.path.join(datadir, "genomes/kraken")
    url = "https://ccb.jhu.edu/software/kraken/dl/minikraken.tgz"
    compress = os.path.join(kraken, os.path.basename(url))
    base, ext = utils.splitext_plus(os.path.basename(url))
    db = os.path.join(kraken, base)
    tooldir = args.tooldir or get_defaults()["tooldir"]
    requests.packages.urllib3.disable_warnings()
    last_mod = urllib.request.urlopen(url).info().get('Last-Modified')
    last_mod = dateutil.parser.parse(last_mod).astimezone(dateutil.tz.tzutc())
    if os.path.exists(os.path.join(tooldir, "bin", "kraken")):
        if not os.path.exists(db):
            is_new_version = True
        else:
            cur_file = glob.glob(os.path.join(kraken, "minikraken_*"))[0]
            cur_version = datetime.datetime.utcfromtimestamp(os.path.getmtime(cur_file))
            is_new_version = last_mod.date() > cur_version.date()
            if is_new_version:
                shutil.move(cur_file, cur_file.replace('minikraken', 'old'))
        if not os.path.exists(kraken):
            utils.safe_makedir(kraken)
        if is_new_version:
            if not os.path.exists(compress):
                subprocess.check_call(["wget", "-O", compress, url, "--no-check-certificate"])
            cmd = ["tar", "-xzvf", compress, "-C", kraken]
            subprocess.check_call(cmd)
            last_version = glob.glob(os.path.join(kraken, "minikraken_*"))
            utils.symlink_plus(os.path.join(kraken, last_version[0]), os.path.join(kraken, "minikraken"))
            utils.remove_safe(compress)
        else:
            print("You have the latest version %s." % last_mod)
    else:
        raise argparse.ArgumentTypeError("kraken not installed in tooldir %s." %
                                         os.path.join(tooldir, "bin", "kraken"))