How to use the pyulog.ULog.HEADER_BYTES function in pyulog

if form_data['public'].decode("utf-8") == 'true':
                            is_public = 1

                file_obj = self.multipart_streamer.get_parts_by_name('filearg')[0]
                upload_file_name = file_obj.get_filename()

                while True:
                    log_id = str(uuid.uuid4())
                    new_file_name = get_log_filename(log_id)
                    if not os.path.exists(new_file_name):
                        break

                # read file header & check if really an ULog file
                header_len = len(ULog.HEADER_BYTES)
                if (file_obj.get_payload_partial(header_len) !=
                        ULog.HEADER_BYTES):
                    if upload_file_name[-7:].lower() == '.px4log':
                        raise CustomHTTPError(
                            400,
                            'Invalid File. This seems to be a px4log file. '
                            'Upload it to <a href="http://logs.uaventure.com">logs.uaventure.com</a>.')
                    raise CustomHTTPError(400, 'Invalid File')

                print('Moving uploaded file to', new_file_name)
                file_obj.move(new_file_name)

                if obfuscated == 1:
                    # TODO: randomize gps data, ...
                    pass

                # generate a token: secure random string (url-safe)

allow_for_analysis = 1
                    if 'public' in form_data:
                        if form_data['public'].decode("utf-8") == 'true':
                            is_public = 1

                file_obj = self.multipart_streamer.get_parts_by_name('filearg')[0]
                upload_file_name = file_obj.get_filename()

                while True:
                    log_id = str(uuid.uuid4())
                    new_file_name = get_log_filename(log_id)
                    if not os.path.exists(new_file_name):
                        break

                # read file header & check if really an ULog file
                header_len = len(ULog.HEADER_BYTES)
                if (file_obj.get_payload_partial(header_len) !=
                        ULog.HEADER_BYTES):
                    if upload_file_name[-7:].lower() == '.px4log':
                        raise CustomHTTPError(
                            400,
                            'Invalid File. This seems to be a px4log file. '
                            'Upload it to <a href="http://logs.uaventure.com">logs.uaventure.com</a>.')
                    raise CustomHTTPError(400, 'Invalid File')

                print('Moving uploaded file to', new_file_name)
                file_obj.move(new_file_name)

                if obfuscated == 1:
                    # TODO: randomize gps data, ...
                    pass