Имя 'cache' не определено django

class CourseListView(TemplateResponseMixin, View): модель = Курс template_name = 'eschool/course/list.html'

def get(self, request, subject=None):
    subjects = cache.get('all_subjects')
    if not subjects:
        subjects = Subject.objects.annotate(total_courses=Count('courses'))
        cache.set('all_subjects', subjects)
    all_courses = Course.objects.annotate(total_modules=Count('modules'))

    if subject:
        subject = get_object_or_404(Subject, slug=subject)
        key = f'subject_{subject.id}_courses'
        courses = cache.get(key)

        if not courses:
            courses = all_courses.filter(subject=subject)
            cache.set(key, courses)
    else:
        courses = cache.get('all_courses')
        if not courses:
            courses = all_courses
            cache.set('all_courses', courses)
    return self.render_to_response({
        'subjects': subjects,
        'subject': subject,
        'courses': courses
        })

from django.core.cache import cache