How to use the stestr.commands.init_command function in stestr

test_dir, top_dir, group_regex = _parse_testrconf()
    elif not os.path.isfile(
        '.testr.conf') and not os.path.isfile('.stestr.conf'):
        msg = ('No .stestr.conf found, please create one.')
        print(msg)
        sys.exit(1)

    regexes = None
    if regex:
        regexes = regex.split()
    serial = not parallel
    if list_tests:
        # TODO(mtreinish): remove init call after list command detects and
        # autocreates the repository
        if not os.path.isdir('.stestr'):
            commands.init_command()
        return commands.list_command(filters=regexes)
    return_code = commands.run_command(filters=regexes, subunit_out=subunit,
                                       concurrency=concur, test_path=test_dir,
                                       top_dir=top_dir,
                                       group_regex=group_regex,
                                       until_failure=until_failure,
                                       serial=serial, pretty_out=pretty,
                                       load_list=load_list,
                                       blacklist_file=blacklist_file,
                                       whitelist_file=whitelist_file,
                                       black_regex=black_regex)

    if slowest:
        sys.stdout.write("\nSlowest Tests:\n")
        commands.slowest_command()
    return return_code

def call_subunit_run(test_id, pretty, subunit):
    env = copy.deepcopy(os.environ)
    cmd_save_results = ['stestr', 'load', '--subunit']
    if not os.path.isdir('.stestr'):
        commands.init_command()

    if pretty:
        # Use subunit run module
        cmd = ['python', '-m', 'subunit.run', test_id]
        ps = subprocess.Popen(cmd, env=env, stdout=subprocess.PIPE)
        # Save subunit results via testr
        pfile = subprocess.Popen(cmd_save_results, env=env,
                                 stdin=ps.stdout, stdout=subprocess.PIPE)
        ps.stdout.close()
        # Transform output via subunit-trace
        proc = subprocess.Popen(['subunit-trace', '--no-failure-debug', '-f'],
                                env=env, stdin=pfile.stdout)
        pfile.stdout.close()
        proc.communicate()
        return proc.returncode
    elif subunit: