                  if settings.USE_TZ:
                      if datetime is None:
                          raise ValueError("Database returned an invalid value "
                                           "in QuerySet.dates(). Are time zone "
                                           "definitions installed?")
                      datetime = datetime.replace(tzinfo=None)
                      datetime = timezone.make_aware(datetime, self.query.tzinfo)
                  yield datetime
  
  def order_modified_iter(cursor, trim, sentinel):
 
</s>
                                         "definitions and pytz installed?")
                  if settings.USE_TZ:
                      if datetime is None:
                          raise ValueError("Database returned an invalid value "
                                           "in QuerySet.dates(). Are time zone "
                                         "definitions and pytz installed?")
                      datetime = datetime.replace(tzinfo=None)
                      datetime = timezone.make_aware(datetime, self.query.tzinfo)
                  yield datetime
  
  def order_modified_iter(cursor, trim, sentinel):
keep keep keep keep replace keep keep keep keep keep
 Fixed test failures on MySQL.

Some tests failed when the time zone definitions were loaded in MySQL
and pytz wasn't installed. This setup isn't supported.
django/db/models/sql/compiler.py