Hi all,

I'm trying to export some products from another platform to Odoo. As far I've understood to create the different variants I should create the product template first and then create several product attribute lines, one for each different attribute. 

I have no issues creating the template, but I'm stuck when it comes to the product attribute lines. Following this forum reply (https://www.odoo.com/es_ES/forum/ayuda-1/question/how-to-create-product-product-variant-using-rpc-101043) I'm currently doing this:

product_line = models.execute_kw(odoo_db, uid, password, 'product.attribute.line', 'create', {    template_id: template_id,    attribute_id: attr.first,    value_ids: [6, 0, [attr.last]]})

Where template_id is, of course, the Odoo template id, attr.first is the ID of the attribute type (size, color, etc - 1 for size in this case) and [attr.last] is an array with the ID of the attribute value ([4]). 

Nevertheless, I'm getting this error when executing the line:

ValueError: dictionary update sequence element #0 has length 1; 2 is required

I have no clue why - I may be using the value_ids format wrong but I can't find what's wrong. 

Any help would be appreciated :)    I'm using Odoo 10.