old_contents: # -*- coding: utf-8 -*-
  ##############################################################################
  # For copyright and license notices, see __openerp__.py file in module root
  # directory
  ##############################################################################
  from openerp import models, fields, api
  
  
  class SalesmanGroup(models.Model):
  
      _name = "sale.salesman.group"
      _description = "Salesman Group"
      _order = "name"
  
      _constraints = [
          (models.Model._check_recursion,
           'Error ! You cannot create recursive '
           'categories.', ['parent_id'])
      ]
  
      @api.multi
      def name_get(self):
          if not len(self._ids):
              return []
          reads = self.read(['name', 'parent_id'])
          res = []
          for record in reads:
              name = record['name']
              if record['parent_id']:
                  name = record['parent_id'][1] + ' / ' + name
              res.append((record['id'], name))
          return res
  
      @api.multi
      def _name_get_fnc(self):
          res = self.name_get()
          return dict(res)
  
      name = fields.Char('Name', required=True, translate=True)
      complete_name = fields.Char(
          compute=_name_get_fnc, string='Name')
      parent_id = fields.Many2one(
          'sale.salesman.group', 'Parent Group', select=True)
      child_id = fields.One2many(
          'sale.salesman.group', 'parent_id',
          string='Children Groups')
  
new_contents: # -*- coding: utf-8 -*-
  ##############################################################################
  # For copyright and license notices, see __openerp__.py file in module root
  # directory
  ##############################################################################
  from openerp import models, fields, api
  
  
  class SalesmanGroup(models.Model):
  
      _name = "sale.salesman.group"
      _description = "Salesman Group"
      _order = "name"
  
      _constraints = [
          (models.Model._check_recursion,
           'Error ! You cannot create recursive '
           'categories.', ['parent_id'])
      ]
  
      @api.multi
      def name_get(self):
          if not len(self.ids):
              return []
          reads = self.read(['name', 'parent_id'])
          res = []
          for record in reads:
              name = record['name']
              if record['parent_id']:
                  name = record['parent_id'][1] + ' / ' + name
              res.append((record['id'], name))
          return res
  
      @api.multi
      def _name_get_fnc(self):
          res = self.name_get()
          return dict(res)
  
      name = fields.Char('Name', required=True, translate=True)
      complete_name = fields.Char(
          compute=_name_get_fnc, string='Name')
      parent_id = fields.Many2one(
          'sale.salesman.group', 'Parent Group', select=True)
      child_id = fields.One2many(
          'sale.salesman.group', 'parent_id',
          string='Children Groups')
  
subject: FIX product_salesman_group/models/sale.py