title: Odoo v9 - Using Onchange, how do you clear what is already entered in a field?
body: <p>I am extending product.template, and I've added a field called uom_class.  When I change this field when editing a product, I'd like to clear what is entered in the Many2One field called "Unit of Measure" (uom_id in product.template). I am doing this because I am also changing the domain for the uom_id, and the existing selection ("Units" by default) will probably not be in that domain.</p>
  
  <p>I've tried the following, as suggested for earlier versions, but it did not work.</p>
  
  <pre><code>@api.onchange('uom_class')
      def onchange_uom_class(self):
        # [...] not shown: previously set new domain for uom_id
        result['value'] ={'uom_id':False}
        return result
  </code></pre>
  
  <p>I've seen other posts suggest I need to add assign it an empty product.uom record, but I have no idea how to do that.  Any help would be greatly appreciated.</p>