Hi All, 

I was trying to save the tracking number in stock.picking model by updating the field, 'carrier_tracking_ref'. So according to the documentation, it should be a straight forward process. I have tried, 

from odoo import api, fields, models, _

from odoo.exceptions import Warning

class StockPicking(models.Model): 

     _inherit = 'stock.picking'
     @api.multi    

     def button_book_shipment(self): 

           for rec in self:
              # self.book_shipment(rec)            

             rec.carrier_tracking_ref = 'TRACKING_NUMBER'   

# I also tried using write method  

             pick = self.env['stock.picking'].browse(46)            

             pick.write({  'carrier_tracking_ref': 'TRACKING_NUMBER' }) 

              raise Warning(_('Booking shipment DONE'))

But neither of these works and the value does not get updated. I wonder if I have missed anything here or how I can update this field? 

If I edit the picking record from the Odoo UI and manually it enter the tracking number, it saves the value properly. How do I do it in code? 

Thanks.