numpy vs list

    try:

      tasks_filename, metadata_filename = self._get_metadata_filename()

      with open(tasks_filename) as fin:

        tasks = json.load(fin)

        tasks = np.array(json.load(fin))

      metadata_df = read_hdf(metadata_filename, 'metadata')

      return tasks, metadata_df

    except Exception as e:

  metadata_filename = os.path.join(data_dir, "metadata.hd5")

  tasks_filename = os.path.join(data_dir, "tasks.json")

  with open(tasks_filename, 'w') as fout:

    json.dump(tasks, fout)

    json.dump(tasks.tolist(), fout)

  hdf = pd.HDFStore(metadata_filename)

  hdf.put('metadata', metadata_df)

  hdf.close()