AttributeError: 'list' object has no attribute 'format'

В моем проекте foodgram необходимо сделать возможность подписыватья на пользователей.
Проверяю через postman.
При переходе на http://127.0.0.1:8000/api/users/1/subscribe/ мне выдает ошибку AttributeError: 'list' object has no attribute 'format'
Буду рад любой помощи!

Python 3.7.9
Django 3.2.16
djangorestframework 3.12.4

class CustomUserViewSet(UserViewSet):
    """ Вьюсет для пользователя с подписками
    через POST&GET. """

    queryset = CustomUser.objects.all()
    serializer_class = CustomUserSerializer
    permission_classes = (IsAuthenticated,)
    pagination_class = LimitPageNumberPagination
    
    @action(detail=True, methods=['POST'], url_path='subscribe')
    def user_subscribe_add(self, request, id):
        user = request.user
        following = get_object_or_404(CustomUser, pk=id)
        serializer = FollowCreateSerializer(
            data={'user': user.id, 'following': id},
            context={'request': request})
        print(serializer)
        serializer.is_valid(raise_exception=True)
        serializer.save()
        follow = get_object_or_404(Follow, user=user, following=following)
        serializer = FollowSerializer(follow.following,
                                      context={'request': request})
        return Response(serializer.data, status=status.HTTP_201_CREATED)

serializer:

class FollowCreateSerializer(serializers.ModelSerializer):
    """ Сериализатор создания объекта Подписки. """

    user = serializers.PrimaryKeyRelatedField(
        queryset=CustomUser.objects.all())
    following = serializers.PrimaryKeyRelatedField(
        queryset=CustomUser.objects.all())


    class Meta:
        fields = ('user', 'following')
        model = Follow
        validators = [
            UniqueTogetherValidator(
                queryset=Follow.objects.all(),
                fields=['user', 'following'],
                message=['Подписка выполнена.']
            )
        ]

    def validate(self, data):
        user = data['user']
        current_follow = data['following']
        if user == current_follow:
            raise serializers.ValidationError(
                ['Подписка на себя невозможна'])
        return data

Traceback:

Internal Server Error: /api/users/1/subscribe/
Traceback (most recent call last):
  File "C:\Dev\foodgram-project-react\venv\lib\site-packages\django\core\handlers\exception.py", line 47, in inner
    response = get_response(request)
  File "C:\Dev\foodgram-project-react\venv\lib\site-packages\django\core\handlers\base.py", line 181, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "C:\Dev\foodgram-project-react\venv\lib\site-packages\django\views\decorators\csrf.py", line 54, in wrapped_view
    return view_func(*args, **kwargs)
  File "C:\Dev\foodgram-project-react\venv\lib\site-packages\rest_framework\viewsets.py", line 125, in view
    return self.dispatch(request, *args, **kwargs)
  File "C:\Dev\foodgram-project-react\venv\lib\site-packages\rest_framework\views.py", line 509, in dispatch
    response = self.handle_exception(exc)
  File "C:\Dev\foodgram-project-react\venv\lib\site-packages\rest_framework\views.py", line 469, in handle_exception
    self.raise_uncaught_exception(exc)
  File "C:\Dev\foodgram-project-react\venv\lib\site-packages\rest_framework\views.py", line 480, in raise_uncaught_exception
    raise exc
  File "C:\Dev\foodgram-project-react\venv\lib\site-packages\rest_framework\views.py", line 506, in dispatch
    response = handler(request, *args, **kwargs)
  File "C:\Dev\foodgram-project-react\backend\foodgram\recipes\views.py", line 48, in user_subscribe_add
    serializer.is_valid(raise_exception=True)
  File "C:\Dev\foodgram-project-react\venv\lib\site-packages\rest_framework\serializers.py", line 227, in is_valid
    self._validated_data = self.run_validation(self.initial_data)
  File "C:\Dev\foodgram-project-react\venv\lib\site-packages\rest_framework\serializers.py", line 428, in run_validation
    self.run_validators(value)
  File "C:\Dev\foodgram-project-react\venv\lib\site-packages\rest_framework\serializers.py", line 461, in run_validators
    super().run_validators(to_validate)
  File "C:\Dev\foodgram-project-react\venv\lib\site-packages\rest_framework\fields.py", line 591, in run_validators
    validator(value, self)
  File "C:\Dev\foodgram-project-react\venv\lib\site-packages\rest_framework\validators.py", line 159, in __call__
    message = self.message.format(field_names=field_names)
AttributeError: 'list' object has no attribute 'format'
[17/Nov/2022 09:11:57] "POST /api/users/1/subscribe/ HTTP/1.1" 500 123997

В FollowCreateSerializer заменил

message=['Подписка выполнена.']

на:

message='Подписка выполнена.'
Вернуться на верх