django component class exampls

models.py

class Course(models.Model):
    class Meta:
        verbose_name = 'Course'
        verbose_name_plural = 'Courses'

    trailer = models.FileField(verbose_name='Trailer', upload_to='course_trailers/')
    price = models.PositiveSmallIntegerField(verbose_name='Price')
    author = models.ForeignKey(CustomUser, on_delete=models.SET_NULL, null=True, blank=True, verbose_name='Author',
                               related_name='courses')
    title = models.CharField(max_length=255, verbose_name='Title')
    description = models.CharField(verbose_name='Description', max_length=2000)

    @property
    def produce_slug(self):
        return '{}-{}'.format(self.title, self.pk)

    @property
    def author_info(self):
        return self.author.__unicode__()

    @property
    def rate(self):
        result = self.rates.aggregate(avg_rate=Avg('rate'))
        return result['avg_rate']

    @property
    def rates_count(self):
        return self.rates.distinct('user').count()

    @property
    def rates_in_percent_by_value(self):
        total_rows_count = CourseRate.objects.filter(course=self).count()
        return CourseRate.objects.filter(course=self).values('rate').annotate(
            value=ExpressionWrapper(Count('rate') * 100 / total_rows_count,
                                    output_field=models.FloatField())).values('rate', 'value')

serializers.py

class UserCreateSerializer(serializers.Serializer):
    email = serializers.EmailField(required=True, trim_whitespace=True)
    password = serializers.CharField(required=True, trim_whitespace=True, min_length=6)
    name = serializers.CharField(required=True, trim_whitespace=True)
    birth_date = serializers.DateField(required=False)
    gender = serializers.ChoiceField(choices=CustomUser.GENDER_CHOICES, required=False)
    phone_number = serializers.CharField(required=False)
    avatar = serializers.ImageField(required=False)

    def create(self, validated_data):
        try:
            firebase_user = firebase_auth.create_user(email=validated_data['email'],
                                                      password=validated_data['password'],
                                                      display_name=validated_data['name'],
                                                      email_verified=False)
            user = CustomUser.objects.create_user(**validated_data, username=firebase_user.uid)
        except (firebase_exceptions.InvalidArgumentError, IntegrityError):
            raise rest_exceptions.ValidationError(detail='Email is already taken.')
        except ValueError:
            raise rest_exceptions.ValidationError(detail='The specified user properties are invalid.')
        return user

views.py

class VerifyEmailAPIView(APIView):
    def get_object(self, key):
        return get_object_or_404(key=key,
                                 queryset=EmailConfirmation.objects.all())

    @swagger_auto_schema(request_body=VerificationKeySerializer)
    def post(self, request):
        serializer = VerificationKeySerializer(data=request.data)
        serializer.is_valid(raise_exception=True)
        email_confirmation = self.get_object(serializer.validated_data['key'])
        try:
            email_confirmation.confirm()
        except KeyExpiredException:
            return Response({'detail': _('Key expired.')}, status=status.HTTP_400_BAD_REQUEST)
        return Response({'detail': _('Email verified.')}, status=status.HTTP_200_OK)