add error trace

        self.message = Message(os.path.join(self.dir_out, "msg.txt"))

        self.time_stamp = TimeStamp(os.path.join(self.dir_out, "time_stamp.txt"))

        self.exit_code = ExitCode(os.path.join(self.dir_out, "exit_code"))

        self.error_trace = ErrorTrace(os.path.join(self.dir_out, "error_trace"))

        if dfs:

            self.dfs = DFS(n_try=5)

        warnings.resetwarnings()

class ErrorTrace:

    def __init__(self, file_path=""):

        self.file_path = file_path

    def __repr__(self):

        return f"< ErrorTrace [{self.file_path}] >"

    def write(self, s: str):

        with open(self.file_path, "w+") as f:

            f.write(s)

class Message:

    def __init__(self, file_path=""):

        self.file_path = file_path