test_20_frequency_at_year failing in 2024

Happy new year, I guess! Seen on 3.0.0, but reproducible ond 9b0f1ba7a173fb9d7c61890886a1f9c62cef92d.

python-crontab> _________________ FrequencyTestCase.test_20_frequency_at_year __________________
python-crontab> 
python-crontab> self = <tests.test_frequency.FrequencyTestCase testMethod=test_20_frequency_at_year>
python-crontab> 
python-crontab>     def test_20_frequency_at_year(self):
python-crontab>         """Frequency at leap year day"""
python-crontab>         job = self.crontab.new(command='at_year')
python-crontab>         job.setall("0 * 3,29 2 *")
python-crontab>         self.assertEqual(job.frequency_at_year(2021), 24)
python-crontab>         self.assertEqual(job.frequency_at_year(2024), 48)
python-crontab> >       self.assertEqual(job.frequency_at_year(), 24)
python-crontab> E       AssertionError: 48 != 24
python-crontab> 
python-crontab> tests/test_frequency.py:189: AssertionError