def mkdtemp(suffix="", prefix=template, dir=None):
    """User-callable function to create and return a unique temporary
    directory.  The return value is the pathname of the directory.

    Arguments are as for mkstemp, except that the 'text' argument is
    not accepted.

    The directory is readable, writable, and searchable only by the
    creating user.

    Caller is responsible for deleting the directory when done with it.
    """

    if dir is None:
        dir = gettempdir()

    names = _get_candidate_names()

    for seq in range(TMP_MAX):
        name = next(names)
        file = _os.path.join(dir, prefix + name + suffix)
        try:
            _os.mkdir(file, 0o700)
            return file
        except FileExistsError:
            continue    # try again

    raise FileExistsError(_errno.EEXIST,
                          "No usable temporary directory name found")
User-callable function to create and return a unique temporary
    directory.  The return value is the pathname of the directory.

    Arguments are as for mkstemp, except that the 'text' argument is
    not accepted.

    The directory is readable, writable, and searchable only by the
    creating user.

    Caller is responsible for deleting the directory when done with it.