old_contents: from survey.tests import BaseTest
  from django.test import override_settings
  from django.conf import settings
  from survey import set_default_settings
  
  
  @override_settings()
  class TestDefaultSettings(BaseTest):
      def test_set_choices_separator(self):
          url = "/admin/survey/survey/1/change/"
          del settings.CHOICES_SEPARATOR
          self.login()
          set_default_settings()
          try:
              self.client.get(url)
          except AttributeError:
              self.fail("AttributeError: survey failed to set CHOICES_SEPARATOR")
  
new_contents: from django.conf import settings
  from django.test import override_settings
  
  from survey import set_default_settings
  from survey.tests import BaseTest
  
  
  @override_settings()
  class TestDefaultSettings(BaseTest):
      def test_set_choices_separator(self):
          url = "/admin/survey/survey/1/change/"
          del settings.CHOICES_SEPARATOR
          self.login()
          set_default_settings()
          try:
              self.client.get(url)
          except AttributeError:
              self.fail("AttributeError: survey failed to set CHOICES_SEPARATOR")
  
subject: Apply black following @gjelsas MR