How to use the jplephem.exceptions.OutOfRangeError function in jplephem

def _at(self, t):
        segment = self.spk_segment
        try:
            position, velocity = segment.compute_and_differentiate(
                t.whole, t.tdb_fraction)
        except OutOfRangeError as e:
            start_time = t.ts.tdb(jd=segment.start_jd)
            end_time = t.ts.tdb(jd=segment.end_jd)
            # TODO: switch to calendar dates in TDB to produce round numbers?
            text = ('ephemeris segment only covers dates %s through %s UT'
                    % (start_time.utc_iso(' '), end_time.utc_iso(' ')))
            mask = e.out_of_range_times
            segment = self.spk_segment
            e = EphemerisRangeError(text, start_time, end_time, mask, segment)
            e.__cause__ = None  # avoid exception chaining in Python 3
            raise e

        return position / AU_KM, velocity / AU_KM, None, None