Hello, 

I'm trying to migrate a module from V13 to V15 and I keep getting the error from the title

I get it from the default_get from a wizard:

@api.model
def default_get(self, fields):
    res = super(ProductCategoryAssign, self).default_get(fields)
    if self.env.context.get('active_model') == 'product.template' and self.env.context.get('active_ids'):
        product_ids = [int(id) for id in self.env.context['active_ids']]
        res['product_ids'] = [(6, 0, [product_ids])]
    return res

I have even tired passing an hardcoded appropriate id and I still get the same error

        res['product_ids'] = [(6, 0, [1])]

Any suggestion would be greatly appreciated