new_contents: from openerp import models, fields, api, _
  from openerp.osv import osv
  from bsddb.dbtables import _columns
  from datetime import datetime
  from dateutil import relativedelta
  import time
  import datetime as only_datetime
  
  
  class account_invoice_line(models.Model):
      _inherit = 'account.invoice.line'
         
      rma_id = fields.Many2one('mrp.repair', 'RMA no')
  
subject: Add rmd id