How to simplify this code - newbie question

[Michael Lind Hjulskov]

Hi :o)

I would like to simplify get_rating to fewer lines of code:

class Product(AbstractProduct):

    ... just a little info about the model fields ...

    title = charfield

    parent = foreignkey(Product, related_name='variants')

    rating = a float

    def is_group - return True if it is a parent product and have variants 

    ...

    @property

    def get_rating(self):

        u"""Return a product's rating - group product's ratings is gathered and presented as one"""

        if self.is_group:

            ratings_count = 0

            if self.rating:

                ratings_sum = self.rating

                ratings_count+=1

            for variant in self.variants.all():

                if variant.rating:

                    ratings_sum += variant.rating

                    ratings_count+=1

            if ratings_count > 0:

                rating = float(ratings_sum) / ratings_count

                return rating

        return self.rating

My best guess is below, but it isnt working.

Will somebody please teach me what I should do and maybe explain to me why it isnt working.

I really want to learn this :o)

class Product(AbstractProduct):

    @property

    def get_rating(self):

        u"""Return a product's rating - group product's ratings is gathered and presented as one"""

        if self.is_group:

            return float(Product.objects.filter(Q(parent__in=self) | Q(pk=self.pk)).aggregate(Avg('rating')))

        return self.rating

Thanks alot :)