I have this code: 

class ResCompany(models.Model):
    _inherit = "res.company"
   code_default = fields.Many2one(comodel_name='info.code', string='Default code', help="Default to the documents")

And in my invoice I want to have the default defined in the company:

class AccountInvoice(models.Model):
    _inherit = "account.invoice"
    @api.depends('company_id')
    @api.model
 def default_code(self):
        if self.company_id:
return self.company_id.cae_default.id
code = fields.Many2one('info.code', string='Code', default=default_code, help="Code to the documents",) 

But when the code enter the function default_code the self.company_id  is empty! I also done a onchange but I realy need a default funtion ... 

Any help ? 

Thanks