How to use the astroplan.exceptions.OldEarthOrientationDataWarning function in astroplan

This will fail and raise OSError if the file is not in the cache.
    """
    if IERS_A_in_cache():
        table = iers.IERS_Auto.open()
        # Use polar motion flag to identify last observation before predictions
        index_of_last_observation = ''.join(table['PolPMFlag_A']).index('IP')
        time_of_last_observation = Time(table['MJD'][index_of_last_observation],
                                        format='mjd')
        time_since_last_update = Time.now() - time_of_last_observation

        # If the IERS bulletin is more than `warn_update` days old, warn user
        if warn_update < time_since_last_update:
            warnmsg = ("Your version of the IERS Bulletin A is {:.1f} days "
                       "old. ".format(time_since_last_update.to(u.day).value) +
                       IERS_A_WARNING)
            warnings.warn(warnmsg, OldEarthOrientationDataWarning)
        return table
    else:
        raise OSError("No IERS A table has been downloaded.")

def _low_precision_utc_to_ut1(self, jd1, jd2):
    """
    When no IERS Bulletin A is available (no internet connection), use low
    precision time conversion by assuming UT1-UTC=0 always.
    This method mimics `~astropy.coordinates.builtin_frames.utils.get_dut1utc`
    """
    try:
        if self.mjd*u.day not in iers.IERS_Auto.open()['MJD']:
            warnings.warn(IERS_A_WARNING, OldEarthOrientationDataWarning)
        return self.delta_ut1_utc

    except (AttributeError, ValueError):
        warnings.warn(IERS_A_WARNING, OldEarthOrientationDataWarning)
        return np.zeros(self.shape)