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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _build_trial_meta(cls, expr_dir):
 """Build meta file for trial. Args: expr_dir (str):
 Directory path of the experiment. Return: A dict of trial meta info. """

        meta_file = os.path.join(expr_dir, EXPR_META_FILE)
        meta = parse_json(meta_file)

        if not meta:
            job_id = expr_dir.split("/")[-2]
            trial_id = expr_dir[-8:]
            params = parse_json(os.path.join(expr_dir, EXPR_PARARM_FILE))
            meta = {
                "trial_id": trial_id,
                "job_id": job_id,
                "status": "RUNNING",
                "type": "TUNE",
                "start_time": os.path.getctime(expr_dir),
                "end_time": None,
                "progress_offset": 0,
                "result_offset": 0,
                "params": params
            }

        if not meta.get("start_time", None):
            meta["start_time"] = os.path.getctime(expr_dir)

        if isinstance(meta["start_time"], float):
            meta["start_time"] = timestamp2date(meta["start_time"])

        if meta.get("end_time", None):
            meta["end_time"] = timestamp2date(meta["end_time"])

        meta["params"] = parse_json(os.path.join(expr_dir, EXPR_PARARM_FILE))

        return meta