How to use the s3transfer.compat.six function in s3transfer

self.osutil = OSUtils()
        self.worker = GetObjectWorker(
            queue=self.queue,
            client_factory=self.client_factory,
            transfer_monitor=self.transfer_monitor,
            osutil=self.osutil
        )
        self.transfer_id = self.transfer_monitor.notify_new_transfer()
        self.bucket = 'bucket'
        self.key = 'key'
        self.remote_contents = b'my content'
        self.temp_filename = self.files.create_file('tempfile', '')
        self.extra_args = {}
        self.offset = 0
        self.final_filename = self.files.full_path('final_filename')
        self.stream = six.BytesIO(self.remote_contents)
        self.transfer_monitor.notify_expected_jobs_to_complete(
            self.transfer_id, 1000)

def add_get_responses(self):
        chunksize = self.config.multipart_chunksize
        for i in range(0, len(self.content), chunksize):
            if i + chunksize > len(self.content):
                stream = six.BytesIO(self.content[i:])
                self.stubber.add_response('get_object', {'Body': stream})
            else:
                stream = six.BytesIO(self.content[i:i+chunksize])
                self.stubber.add_response('get_object', {'Body': stream})

self.stubbed_client = self.manager.StubbedClient()
        self.mock_client_factory = self.client_factory_patch.start()
        self.mock_client_factory.\
            return_value.create_client.return_value = self.stubbed_client

        self.files = FileCreator()

        self.config = ProcessTransferConfig(
            max_request_processes=1
        )
        self.downloader = ProcessPoolDownloader(config=self.config)
        self.bucket = 'mybucket'
        self.key = 'mykey'
        self.filename = self.files.full_path('filename')
        self.remote_contents = b'my content'
        self.stream = six.BytesIO(self.remote_contents)

def test_download_file_ranged_download(self):
        half_of_content_length = int(len(self.remote_contents)/2)
        self.stubbed_client.add_response(
            'head_object', {'ContentLength': len(self.remote_contents)})
        self.stubbed_client.add_response(
            'get_object', {
                'Body': six.BytesIO(
                    self.remote_contents[:half_of_content_length])}
        )
        self.stubbed_client.add_response(
            'get_object', {
                'Body': six.BytesIO(
                    self.remote_contents[half_of_content_length:])}
        )
        downloader = ProcessPoolDownloader(
            config=ProcessTransferConfig(
                multipart_chunksize=half_of_content_length,
                multipart_threshold=half_of_content_length,
                max_request_processes=1
            )
        )
        with downloader:
            downloader.download_file(self.bucket, self.key, self.filename)
        self.assert_contents(self.filename, self.remote_contents)

def test_download_for_seekable_filelike_obj(self):
        self.add_head_object_response()
        self.add_successful_get_object_responses()

        # Create a file-like object to test. In this case, it is a BytesIO
        # object.
        bytes_io = six.BytesIO()

        future = self.manager.download(
            self.bucket, self.key, bytes_io, self.extra_args)
        future.result()

        # Ensure that the contents are correct
        bytes_io.seek(0)
        self.assertEqual(self.content, bytes_io.read())

{
                'method': 'head_object',
                'service_response': {
                    'ContentLength': len(self.content)
                }
            },
            {
                'method': 'get_object',
                'service_response': {
                    'Body': six.BytesIO(self.content[0:4])
                }
            },
            {
                'method': 'get_object',
                'service_response': {
                    'Body': six.BytesIO(self.content[4:8])
                }
            },
            {
                'method': 'get_object',
                'service_response': {
                    'Body': six.BytesIO(self.content[8:])
                }

def open_nonseekable(self, filename, mode):
        self.open_call_args.append((filename, mode))
        return NonSeekableWriter(six.BytesIO(self.content))

def test_upload_for_seekable_filelike_obj_that_has_been_seeked(self):
        self.add_put_object_response_with_default_expected_params()
        bytes_io = six.BytesIO(self.content)
        seek_pos = 5
        bytes_io.seek(seek_pos)
        future = self.manager.upload(
            bytes_io, self.bucket, self.key, self.extra_args)
        future.result()
        self.assert_expected_client_calls_were_correct()
        self.assertEqual(b''.join(self.sent_bodies), self.content[seek_pos:])

def test_upload_for_seekable_filelike_obj(self):
        self.add_create_multipart_response_with_default_expected_params()
        self.add_upload_part_responses_with_default_expected_params()
        self.add_complete_multipart_response_with_default_expected_params()
        bytes_io = six.BytesIO(self.content)
        future = self.manager.upload(
            bytes_io, self.bucket, self.key, self.extra_args)
        future.result()
        self.assert_expected_client_calls_were_correct()
        self.assert_upload_part_bodies_were_correct()

def test_is_compatible_bytes_io(self):
        self.assertTrue(
            self.upload_input_manager.is_compatible(six.BytesIO()))