By default Odoo adds Product-Title and Product-Description to the Invoice order.line Description.

I would like to have it slightly different:

Product Title (aka name) Product-Variants (p.ex. red, size L and so on...)

Like:
Nike Shirt (Red, XL)

How do i do that? I found a module that comes close, but somehow i'm Stuck! https://www.odoo.com/apps/modules/8.0/account_invoice_line_description/

Here is the relevant code from the module i found - It adds only the Product Description to the order.line.description --> So changing that to product title and Variants should not be that hard... should... i need help.

class AccountInvoiceLine(models.Model):
_inherit = "account.invoice.line"

@api.multi
def product_id_change(
        self, product, uom_id, qty=0, name='', type='out_invoice',
        partner_id=False, fposition_id=False, price_unit=False,
        currency_id=False, company_id=None
):
    res = super(AccountInvoiceLine, self).product_id_change(
        product, uom_id, qty=qty,
        name=name, type=type, partner_id=partner_id,
        fposition_id=fposition_id, price_unit=price_unit,
        currency_id=currency_id,  company_id=company_id
    )
    if product:
        if self.user_has_groups(
                'account_invoice_line_description.'
                'group_use_product_description_per_inv_line',
        ):
            product = self.env['product.product'].browse(product)
            if product.description:
                if 'value' not in res:
                    res['value'] = {}
                res['value']['name'] = product.description
    return res

Thank you very much!