I have a Tender model and a Product model. There is a foreign key relationship between Tender and product.
Now I want to update a tender instance where I provide tender and product data. The data format is multipart/form-data. But every time get the following error

{
“products”: [
“This field is required.”
]
}

I am providing the code so that you guys can understand things properly

This is the view class

@extend_schema(tags=[OpenApiTags.TMS_TENDER])
class TenderUpdateView(generics.UpdateAPIView):
    permission_classes = []
    queryset = Tender.objects.all()
    serializer_class = TenderPreSubmissionSerializer
    lookup_field = "id"
    parser_classes = [MultiPartParser]

    def get_queryset(self):
        id = self.kwargs.get("id")
        return Tender.objects.filter(id=id)

This is the serializer

class TenderPreSubmissionSerializer(serializers.ModelSerializer):
    products = ProductSerializer(many=True)

    class Meta:
        model = Tender
        fields = [
            "products",
            "is_open",
            "procuring_entity",
            "ministry",
            "bg_amount",
            "bg_attachment",
            "bg_issue_date",
            "bg_validity_date",
            "is_bg_extended",
        ]

    def update(self, instance, validated_data):
        # Extract products data
        products_data = validated_data.pop("products")

        # Update tender instance
        instance = super().update(instance, validated_data)

        # Create a mapping of existing products by ID
        existing_products = {product.id: product for product in instance.products.all()}

        # Update or create products
        for product_data in products_data:
            product_id = product_data.get("id")
            if product_id and product_id in existing_products:
                # Update existing product
                product = existing_products.pop(product_id)
                for attr, value in product_data.items():
                    setattr(product, attr, value)
                product.save()
            else:
                # Create new product
                Product.objects.create(**product_data)

        # Delete products that are not in the new list
        for product in existing_products.values():
            product.delete()

        return instance