How to use the boto3.s3.transfer.S3Transfer function in boto3

def test_download_requires_string_filename(self):
        transfer = S3Transfer(client=mock.Mock())
        with self.assertRaises(ValueError):
            transfer.download_file(bucket='foo', key='bar', filename=object())

def setUp(self):
        self.client = mock.Mock()
        self.manager = mock.Mock(TransferManager(self.client))
        self.transfer = S3Transfer(manager=self.manager)
        self.callback = mock.Mock()

def upload_files(s3_client, filenames, bucket_name):

    print('Uploading files to the bucket {}...'.format(bucket_name))
    for f in filenames:
        try:
            key = f.split('/')[-2:]
            key = key[0] + '/' + key[1]
            tc = boto3.s3.transfer.TransferConfig()
            t = boto3.s3.transfer.S3Transfer(client=s3_client, config=tc)
            t.upload_file(f, bucket_name, key, extra_args={'ACL': 'public-read'})

            file_url = 'https://{}.s3.amazonaws.com/{}'.format(bucket_name, key)
            print('The uploaded file is public and accessible with the following url: \n    {}'.format(file_url))
        except S3UploadFailedError:
            print('File upload is not successful: PutObject permission missing.')

with Image(filename=file) as img:
        crop_center(img)
        img.format = 'png'
        img.save(filename=os.path.join(UPLOAD_FOLDER, content_type, filename_template % (image_id, 'raw')))

    # sizes
    for (name, size) in sizes:
        with Image(filename=file) as img:
            crop_center(img)
            img.sample(size, size)
            img.format = 'png'
            img.save(filename=os.path.join(UPLOAD_FOLDER, content_type, filename_template % (image_id, name)))

    if AWS_BUCKET:
        s3 = boto3.client('s3')
        transfer = S3Transfer(s3)
        transfer.upload_file(
            os.path.join(UPLOAD_FOLDER, content_type, filename_template % (image_id, 'raw')), 
            AWS_BUCKET, 
            os.path.join(content_type, filename_template % (image_id, 'raw')),
            extra_args={'ACL': 'public-read', 'ContentType': 'image/png'}
            )
        os.remove(os.path.join(UPLOAD_FOLDER, content_type, filename_template % (image_id, 'raw')))

        for (name, size) in sizes:
            transfer.upload_file(
                os.path.join(UPLOAD_FOLDER, content_type, filename_template % (image_id, name)), 
                AWS_BUCKET, 
                os.path.join(content_type, filename_template % (image_id, name)),
                extra_args={'ACL': 'public-read', 'ContentType': 'image/png'}
                )
            os.remove(os.path.join(UPLOAD_FOLDER, content_type, filename_template % (image_id, name)))

def download(bucket, key, file_path, session=None):
    """Download a file from S3 to the given path."""
    s3_client = _get_client(session)

    transfer = S3Transfer(s3_client)
    transfer.download_file(bucket, key, file_path)
    return file_path

# create intermediate and intermediate_tmp directories
    os.makedirs(intermediate_path)
    os.makedirs(tmp_dir_path)

    # configure unique s3 output location similar to how SageMaker platform does it
    # or link it to the local output directory
    url = urlparse(s3_output_location)
    if url.scheme == "file":
        logger.debug("Local directory is used for output. No need to sync any intermediate output.")
        return
    elif url.scheme != "s3":
        raise ValueError("Expecting 's3' scheme, got: %s in %s" % (url.scheme, url))

    # create s3 transfer client
    client = boto3.client("s3", region)
    s3_transfer = s3transfer.S3Transfer(client)
    s3_uploader = {
        "transfer": s3_transfer,
        "bucket": url.netloc,
        "key_prefix": os.path.join(
            url.path.lstrip("/"), os.environ.get("TRAINING_JOB_NAME", ""), "output", "intermediate"
        ),
    }

    # Add intermediate folder to the watch list
    inotify = inotify_simple.INotify()
    watch_flags = inotify_simple.flags.CLOSE_WRITE | inotify_simple.flags.CREATE
    watchers = {}
    wd = inotify.add_watch(intermediate_path, watch_flags)
    watchers[wd] = ""

    # start subprocess to sync any files from intermediate folder to s3