In model sale order line I add a field "image_ref", I'd like to pass the value of this field to an icon in the sale order line view. So every time it change the product. change the icon.

I know that I can do this using fields_view_get(), but I don't know exactly how it works, I understand that everything does the py and the view is not modified.

I'm beginning with this.

def fields_view_get(self, cr, uid, view_id=None, view_type='tree', context=None, toolbar=False,submenu=False):
        result = super(sale_order_line, self).fields_view_get(cr, uid, view_id, view_type, context, toolbar,submenu)

        active_id = context.get('active_id', False)

        res['fields'][field]['icon'] = image_desc