Недопустимая строка формата, хотя не было указано никакого формата

Я получаю ошибку "Invalid format string" при тестировании следующего представления:

class CouponListView(generics.ListAPIView):
   permission_classes = [IsAuthenticated, ]
   queryset = Coupon.objects.all()
   
   def list(self, request, format=None):
      queryset = request.user.coupons.all()
      serializer = CouponSerializer(queryset, many=True)
      return Response(serializer.data)

Вот CouponSerializer:

class CouponSerializer(serializers.ModelSerializer):
    courses = serializers.PrimaryKeyRelatedField(
        many=True, read_only=True)
    class Meta:
        model = Coupon
        exclude = ['users']

Наконец, вот модель Coupon:

class Coupon(models.Model):
   token = models.CharField(max_length=30)
   users = models.ManyToManyField(CustomUser, related_name='coupons')
   courses = models.ManyToManyField(Course, related_name='coupons')
   discount = models.IntegerField()
   created = models.DateTimeField()
   expiry = models.DateTimeField()

   class Meta:
      ordering = ['token']

   def __str__(self):
        return self.token

Насколько я понимаю, для created и expiry должен использоваться стандартный формат даты/времени. Однако я получаю следующее:

Internal Server Error: /content/coupons/
Traceback (most recent call last):
  File "C:\Dropbox\Parnasa\Web\drmeir\env\lib\site-packages\django\core\handlers\exception.py", line 47, in inner
    response = get_response(request)
  File "C:\Dropbox\Parnasa\Web\drmeir\env\lib\site-packages\django\core\handlers\base.py", line 181, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "C:\Dropbox\Parnasa\Web\drmeir\env\lib\site-packages\django\views\decorators\csrf.py", line 54, in wrapped_view
    return view_func(*args, **kwargs)
  File "C:\Dropbox\Parnasa\Web\drmeir\env\lib\site-packages\django\views\generic\base.py", line 70, in view
    return self.dispatch(request, *args, **kwargs)
  File "C:\Dropbox\Parnasa\Web\drmeir\env\lib\site-packages\rest_framework\views.py", line 509, in dispatch
    response = self.handle_exception(exc)
  File "C:\Dropbox\Parnasa\Web\drmeir\env\lib\site-packages\rest_framework\views.py", line 469, in handle_exception
    self.raise_uncaught_exception(exc)
  File "C:\Dropbox\Parnasa\Web\drmeir\env\lib\site-packages\rest_framework\views.py", line 480, in raise_uncaught_exception
    raise exc
  File "C:\Dropbox\Parnasa\Web\drmeir\env\lib\site-packages\rest_framework\views.py", line 506, in dispatch
    response = handler(request, *args, **kwargs)
  File "C:\Dropbox\Parnasa\Web\drmeir\env\lib\site-packages\rest_framework\generics.py", line 199, in get
    return self.list(request, *args, **kwargs)
  File "C:\Users\Meir\web\drmeir\content\views.py", line 56, in list
    return Response(serializer.data)
  File "C:\Dropbox\Parnasa\Web\drmeir\env\lib\site-packages\rest_framework\serializers.py", line 745, in data
    ret = super().data
  File "C:\Dropbox\Parnasa\Web\drmeir\env\lib\site-packages\rest_framework\serializers.py", line 246, in data
    self._data = self.to_representation(self.instance)
  File "C:\Dropbox\Parnasa\Web\drmeir\env\lib\site-packages\rest_framework\serializers.py", line 663, in to_representation
    return [
  File "C:\Dropbox\Parnasa\Web\drmeir\env\lib\site-packages\rest_framework\serializers.py", line 664, in <listcomp>
    self.child.to_representation(item) for item in iterable
  File "C:\Dropbox\Parnasa\Web\drmeir\env\lib\site-packages\rest_framework\serializers.py", line 515, in to_representation
    ret[field.field_name] = field.to_representation(attribute)
  File "C:\Dropbox\Parnasa\Web\drmeir\env\lib\site-packages\rest_framework\fields.py", line 1240, in to_representation
    return value.strftime(output_format)
ValueError: Invalid format string

Что я упускаю и как я могу это исправить?

Вернуться на верх