Ключевая ошибка в колбе

Question

Я получаю сообщение об ошибке при открытии страницы в браузере, созданном с помощью flask.

Я думаю, что ошибка заключается в использовании get_cache.Я пытался решить эту ошибку, но не смог получить точное решение.Я импортировал кэш с помощью кеша импорта flask_caching. Код для main_views, где я получаю сообщение об ошибке, выглядит следующим образом:

class InvalidUser(Exception):
    pass

class InvalidAction(Exception):
    pass

@main_views.route('/')
def index():
    return render_template("index.html")

class BaseQuestionView(MethodView):
    decorators = [auth_required('session')]

    def get_model(self, id):
        question = Question.query.filter_by(id=id).first()
        if question.user == current_user:
            return question
        else:
            raise InvalidUser()

    def get_cache_key(self, id):
        return "{0}_question_status".format(id)

    def get_cache(self, id):
        from app import cache
        return cache.get(self.get_cache_key(id))

    def set_cache(self, id, val):
        from app import cache
        return cache.set(self.get_cache_key(id), val)

class QuestionView(BaseQuestionView):
    def get_questions(self):
        questions = current_user.questions
        for q in questions:
            q.status = self.get_cache(q.id)
        return questions

    def get(self):
        form_obj = QuestionForm()
        form = render_template("forms/question.html", form=form_obj)
        return render_template("questions.html", questions=self.get_questions(), form=form)


    def post(self):
        form_obj = QuestionForm()
        if form_obj.validate_on_submit():
            form_obj.save()
            return redirect(url_for('main_views.questions'))
        form = render_template("forms/question.html", form=form_obj)

        return render_template("questions.html", questions=self.get_questions(), form=form)

main_views.add_url_rule('/questions', view_func=QuestionView.as_view('questions'))

class QuestionDetailView(BaseQuestionView):

    def get_upload_form(self, model):
        upload_obj = EssayUploadForm()
        upload_form = render_template("forms/upload.html", form=upload_obj, question=model)
        return upload_form

    def get(self, id):
        model = self.get_model(id)
        form_obj = EssayForm()

        form = render_template("forms/essay.html", form=form_obj, question=model)
        return render_template("question.html", question=model, form=form, status=self.get_cache(id), upload_form=self.get_upload_form(model))

    def post(self, id):
        form_obj = EssayForm()
        model = self.get_model(id)
        if form_obj.validate_on_submit():
            form_obj.save(model)
            return redirect(url_for('main_views.question_detail', id=id))
        form = render_template("forms/essay.html", form=form_obj, question=model)
        return render_template("question.html", question=model, form=form, status=self.get_cache(id), upload_form=self.get_upload_form(model))

    def delete(self, id):
        from app import db
        question = self.get_model(id)
        db.session.delete(question)
        db.session.commit()
        return jsonify({})

main_views.add_url_rule('/question/<int:id>', view_func=QuestionDetailView.as_view('question_detail'))

class QuestionActionView(BaseQuestionView):
    actions = ["create", "create_and_score", ]

    def create(self, model):
        from core.tasks.tasks import create_model
        task_status = create_model.delay(model.id)
        return task_status.id

    def create_and_score(self, model):
        from core.tasks.tasks import create_and_score
        task_status = create_and_score.delay(model.id)
        return task_status.id

    def get(self, id, action):
        model = self.get_model(id)
        if action not in self.actions:
            raise InvalidAction()
        task_id = getattr(self, action)(model)
        self.set_cache(id, url_for('main_views.task_status', task_id=task_id))
        return jsonify({})

main_views.add_url_rule('/question/<int:id>/<string:action>', view_func=QuestionActionView.as_view('question_action'))

class EssayUploadView(BaseQuestionView):

    def post(self, id):
        form_obj = EssayUploadForm()
        if form_obj.validate_on_submit():
            model = self.get_model(id)
            file = request.files['upload']
            form_obj.save(model, file)

        return redirect(url_for('main_views.question_detail', id=id))

main_views.add_url_rule('/question/<int:id>/upload_essays', view_func=EssayUploadView.as_view('essay_upload'))

class BaseEssayView(MethodView):
    decorators = [auth_required('session')]

    def get_model(self, id):
        essay = Essay.query.filter_by(id=id).first()
        if essay.question.user == current_user:
            return essay
        else:
            raise InvalidUser()

    def get_cache_key(self, id):
        return "{0}_essay_status".format(id)

    def get_cache(self, id):
        from app import cache
        return cache.get(self.get_cache_key(id))

    def set_cache(self, id, val):
        from app import cache
        return cache.set(self.get_cache_key(id), val)

class EssayDetailView(BaseEssayView):

    def delete(self, id):
        from app import db
        essay = self.get_model(id)
        db.session.delete(essay)
        db.session.commit()
        return jsonify({})

main_views.add_url_rule('/essay/<int:id>', view_func=EssayDetailView.as_view('essay_detail'))

class EssayActionView(BaseEssayView):
    actions = ["score", ]

    def score(self, model):
        from core.tasks.tasks import score_essay
        task_status = score_essay.delay(model.id)
        return task_status.id

    def get(self, id, action):
        model = self.get_model(id)
        if action not in self.actions:
            raise InvalidAction()
        task_id = getattr(self, action)(model)
        self.set_cache(id, url_for('main_views.task_status', task_id=task_id))
        return jsonify({})

main_views.add_url_rule('/essay/<int:id>/<string:action>', view_func=EssayActionView.as_view('essay_action'))

class TaskStatusView(MethodView):
    decorators = [auth_required('session')]

    def get(self, task_id):
        from app import celery

        result = celery.AsyncResult(task_id)
        state, retval = result.state, result.result
        response_data = dict(id=task_id, status=state)
        if state in states.EXCEPTION_STATES:
            traceback = result.traceback
            response_data.update({'exc': get_full_cls_name(retval.__class__),
                                  'traceback': traceback})
        return jsonify({'task': response_data})

main_views.add_url_rule('/tasks/<string:task_id>', view_func=TaskStatusView.as_view('task_status'))

Traceback:

 File "C:\Users\HP\Downloads\EssayGradingSystem\venv\lib\site-packages\flask\app.py", line 2328, in __call__
return self.wsgi_app(environ, start_response)
File "C:\Users\HP\Downloads\EssayGradingSystem\venv\lib\site-packages\flask\app.py", line 2314, in wsgi_app
response = self.handle_exception(e)
File "C:\Users\HP\Downloads\EssayGradingSystem\venv\lib\site-packages\flask\app.py", line 1760, in handle_exception
reraise(exc_type, exc_value, tb)
File "C:\Users\HP\Downloads\EssayGradingSystem\venv\lib\site-packages\flask\app.py", line 2311, in wsgi_app
response = self.full_dispatch_request()
File "C:\Users\HP\Downloads\EssayGradingSystem\venv\lib\site-packages\flask\app.py", line 1834, in full_dispatch_request
rv = self.handle_user_exception(e)
File "C:\Users\HP\Downloads\EssayGradingSystem\venv\lib\site-packages\flask\app.py", line 1737, in handle_user_exception
reraise(exc_type, exc_value, tb)
File "C:\Users\HP\Downloads\EssayGradingSystem\venv\lib\site-packages\flask\app.py", line 1832, in full_dispatch_request
rv = self.dispatch_request()
File "C:\Users\HP\Downloads\EssayGradingSystem\venv\lib\site-packages\flask\app.py", line 1818, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)
File "C:\Users\HP\Downloads\EssayGradingSystem\venv\lib\site-packages\flask_security\decorators.py", line 156, in decorated_view
return fn(*args, **kwargs)
File "C:\Users\HP\Downloads\EssayGradingSystem\venv\lib\site-packages\flask\views.py", line 88, in view
return self.dispatch_request(*args, **kwargs)
File "C:\Users\HP\Downloads\EssayGradingSystem\venv\lib\site-packages\flask\views.py", line 158, in dispatch_request
return meth(*args, **kwargs)
File "C:\Users\HP\Downloads\EssayGradingSystem\core\web\main_views.py", line 57, in get
return render_template("questions.html", questions=self.get_questions(), form=form)
File "C:\Users\HP\Downloads\EssayGradingSystem\core\web\main_views.py", line 51, in get_questions
q.status = self.get_cache(q.id)
File "C:\Users\HP\Downloads\EssayGradingSystem\core\web\main_views.py", line 41, in get_cache
return cache.get(self.get_cache_key(id))
File "C:\Users\HP\Downloads\EssayGradingSystem\venv\lib\site-packages\flask_caching\__init__.py", line 250, in get
return self.cache.get(*args, **kwargs)
File "C:\Users\HP\Downloads\EssayGradingSystem\venv\lib\site-packages\flask_caching\__init__.py", line 246, in cache
return app.extensions["cache"][self]
KeyError: <flask_caching.Cache object at 0x000000000606C6D8>