So I'm trying to stop the "product_uom" field in the supplierinfo model from changing when I change the "uom_po_id" field in the product template, but I think I'm missing something. 

I inherited the model and changed the "product_uom" field to not be related to "uom_po_id" anymore, and when the record is created I assign the correct uom, this way it's correct at first but doesn't change automatically.

I thought this would be enough to stop the uom from changing, but it still does. Maybe I'm missing some onchange method but I can't seem to find the correct one, if there is any.

Here's the relevant code:

from odoo import api, fields, models


class ProductSupplierInfo(models.Model):

    _inherit = 'product.supplierinfo'

    product_uom = fields.Many2one('uom.uom', string='Unit of Measure', help="This comes from the product form.")

     @api.model
     def create(self, vals_list):

        self.product_uom = self.product_tmpl_id.uom_po_id

        return super(ProductSupplierInfo, self).create(vals_list)