Why it is false, this is the code
from import,
    
import
    
from time, date, time
    
from odoo.addons.base import
    
class AccountInvoice (models.Model)
    
    _inherit = 'account.invoice' 
    
    backorder_id fields.Many2one = ('stock .picking' 'Back Order of' required = True )  
    
    date_invoice = fields.Date ("Invoices:")
    
    
    
    @ api.multi
    
    def _write (self, vals):
    
        res = super (AccountInvoice, self) ._ write (vals)
    
        print ("Min_Date:", self. backorder_id.min_date ) 
        print ('=============================')
    
        print ("Invoice:" + self.date_invoice)
    
        return res
This code returns False, i want to get the date value of min_date but what I get is the boolean value False?
Thank u again
