I'm trying to download a text file but when I click the button, it respondes with a 404 error, what am i doing wrong?

from odoo import models, fields

import base64
class HrEmployee(models.Model):   

     _inherit = "hr.employee"
    your_file = fields.Binary("My_file.txt")

    defaction_test_function(self):               

        data = "Your text goes here"        

        self.your_file = base64.b64encode(data.encode())
        return {            

            'type': 'ir.actions.act_url',           

             'url': '/web/content/hr_employee/%s/custom_addon/models/%s?download=true' % (self.id, "My_File.txt"),       

            }

thanks in advice, every help is appreciated