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.

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)