How to use the gdbgui.htmllistformatter function in gdbgui

raw_source_code_list[i] = " "
                raw_source_code_lines_of_interest = raw_source_code_list[
                    (start_line - 1) : (end_line)
                ]
            try:
                lexer = get_lexer_for_filename(path)
            except Exception:
                lexer = None

            if lexer and highlight:
                highlighted = True
                # convert string into tokens
                tokens = lexer.get_tokens("\n".join(raw_source_code_lines_of_interest))
                # format tokens into nice, marked up list of html
                formatter = (
                    htmllistformatter.HtmlListFormatter()
                )  # Don't add newlines after each line
                source_code = formatter.get_marked_up_list(tokens)
            else:
                highlighted = False
                source_code = raw_source_code_lines_of_interest

            return jsonify(
                {
                    "source_code_array": source_code,
                    "path": path,
                    "last_modified_unix_sec": last_modified,
                    "highlighted": highlighted,
                    "start_line": start_line,
                    "end_line": end_line,
                    "num_lines_in_file": num_lines_in_file,
                }