docs: def t_measures(dirname, time_func, measure_func):
      """Calculate a measure over time for a single output directory,
      and its uncertainty.
  
      Parameters
      ----------
      dirname: str
          Path to a model output directory.
      time_func: function
          Function which takes a :class:`Model` instance as a single argument,
          and returns its time.
      measure_func: function
          Function which takes a :class:`Model` instance as a single argument,
          and returns the measure of interest, and its uncertainty.
  
      Returns
      -------
      ts: np.ndarray
          Times.
      measures: np.ndarray
          Measures.
      measure_errs: np.ndarray
          Measure uncertainties.
      """
      ts, measures, measure_errs = [], [], []
      for fname in get_filenames(dirname):
          m = filename_to_model(fname)
          ts.append(time_func(m))
          meas, meas_err = measure_func(m)
          measures.append(meas)
          measure_errs.append(meas_err)
      return np.array(ts), np.array(measures), np.array(measure_errs)