title: Odoo new Api change onchange field.Selection
body: <p>How can I cumpute field.Selection???</p>
  
  <pre><code>listing_type = fields.Selection(string="Format", selection=[('Chinese', 'Auction'),
                                                              ('FixedPriceItem', 'Fixed Price')], required=True)
  listing_duration = fields.Selection([
      ('Days_1', '1 days'),
      ('Days_3', '3 days'),
      ('Days_5', '5 days'),
      ('Days_7', '7 days'),
      ('Days_10', '10 days'),
      ('Days_30', '30 days'),
      ('GTC', 'GTC'),
  ], string="Duration", required=True, compute='_return_listing_duration')
  
  
  @api.one
  @api.depends('listing_type')
  def _return_listing_duration(self):
      if not self.listing_type:
          return
      if self.listing_type == 'Chinese':
          self.listing_duration.selection = [
              ('Days_1', '1 days'),
              ('Days_3', '3 days'),
              ('Days_5', '5 days'),
              ('Days_7', '7 days'),
              ('Days_10', '10 days')
          ]
      elif self.listing_type == 'FixedPriceItem':
          self.listing_duration.selection = [
              ('Days_3', '3 days'),
              ('Days_5', '5 days'),
              ('Days_7', '7 days'),
              ('Days_10', '10 days'),
              ('Days_30', '30 days'),
              ('GTC', 'GTC')
          ]
  </code></pre>
  
  <p>My method _return_listing_duration unfortunately not working.
  _return_listing_duration()
  -> ('Days_10', '10 days')</p>