old_contents: import unittest
  from hypothesis import given
  from hypothesis.extra.datetime import datetimes
  
  import qual
  
  from datetime import date
  
  class TestIsoUtils(unittest.TestCase):
      @given(datetimes())
      def test_round_trip_date(self, dt):
          d = dt.date()
          self.assertEqual(qual.iso_to_gregorian(*d.isocalendar()), d)
  
  
new_contents: import unittest
  from hypothesis import given
  from hypothesis.extra.datetime import datetimes
  
  import qual
  
  from datetime import date
  
  class TestIsoUtils(unittest.TestCase):
      @given(datetimes(timezones=[]))
      def test_round_trip_date(self, dt):
          d = dt.date()
          self.assertEqual(qual.iso_to_gregorian(*d.isocalendar()), d)
  
  
subject: Use timezones=[] to underline that we only care about dates.