ManyRelatedManager object has no attribute 'product'

When trying to POST to create a store, I get the following error

Got AttributeError when trying to get value for a field product

in serializer StoreCategorySerializer

. The serializer field may not be named correctly and does not match any attribute or key in the instance ManyRelatedManager

. Exception source: ManyRelatedManager has no product attribute.

Although I am getting the error, the data is being persisted to the database.

Serializers.py

class StoreCreateSerializer(ModelSerializer):
    store_categories = StoreCategorySerializer()
    merchant = UserSerializer()
    class Meta:
        model = Store
        fields=("id",
                "merchant",
                "store_categories",
                "name_of_legal_entity",
                "pan_number",
                "registered_office_address",
                "name_of_store",
                "store_contact_number",
                "store_long",
                "store_lat",
                "store_start_time",
                "store_end_time",
                "store_off_day",
                )
    def create(self,validated_data):
        store_categories_data = validated_data.pop('store_categories')
        merchant_data = validated_data.pop('merchant')
        for merchantKey, merchantVal in merchant_data.items():
            try:
                merchant,created = User.objects.get_or_create(username=merchantVal)
                print('merchant',merchant)
                validated_data['merchant']=merchant
                store = Store.objects.create(**validated_data)
                image = store_categories_data["product"].pop("image")
                print('image pop results',image)
                '''
                image pop results OrderedDict([('image', <InMemoryUploadedFile: grocery.jpg (image/jpeg)>)])
                '''
                image_instance = ProductImage(**image)
                print('image_instance',image_instance)
                image_instance.save()
                product = store_categories_data["product"]
                product_instance = Product(
                                            store=store,
                                            image=image_instance,
                                            name_of_product=product['name_of_product'],
                                            description=product['description'],
                                            price=product['price'],
                                            active=product['active']
                                        )
                product_instance.save()
                store_category = store_categories_data['store_category']
                store_category = StoreCategory(product=product_instance, store_category=store_category)
                store_category.product.store = store
                store_category.save()
                return store
            except User.DoesNotExist:
                raise NotFound('not found')

      

        
        
        
      

    

Models.py

class Store(models.Model):
    merchant = models.ForeignKey(User)
    name_of_legal_entity = models.CharField(max_length=250)
    name_of_store = models.CharField(max_length=100)
    store_off_day = MultiSelectField(choices=DAY, max_length=7, default='Sat')
    store_categories = models.ManyToManyField('StoreCategory',blank=True)

class Product(models.Model):
    store = models.ForeignKey(Store)
    image = models.ForeignKey('ProductImage',blank=True,null=True)
    name_of_product = models.CharField(max_length=120)
    active = models.BooleanField(default=True)

class ProductImage(models.Model):
    image = models.ImageField(upload_to='products/images/')

    @property
    def imageName(self):
        return str(os.path.basename(self.image.name))


class StoreCategory(models.Model):
    product = models.ForeignKey(Product,null=True, on_delete=models.CASCADE,related_name="store_category")
    store_category = models.CharField(choices=STORE_CATEGORIES, default='GROCERY', max_length=10)