old_contents: # -*- encoding: utf-8 -*-
  ##############################################################################
  # For copyright and license notices, see __openerp__.py file in root directory
  ##############################################################################
  
  from openerp import models, api, _
  
  
  class SaleOrderLine(models.Model):
      _inherit = 'sale.order.line'
  
      @api.multi
      def button_save_data(self):
          self = self
  
      @api.multi
      def button_details(self):
          context = self.env.context.copy()
          context['view_buttons'] = True
          view = {
              'name': _('Details'),
              'view_type': 'form',
              'view_mode': 'form',
              'res_model': 'sale.order.line',
              'view_id': False,
              'type': 'ir.actions.act_window',
              'target': 'new',
              'readonly': True,
              'res_id': self.id,
              'context': context
          }
          return view
  
new_contents: # -*- encoding: utf-8 -*-
  ##############################################################################
  # For copyright and license notices, see __openerp__.py file in root directory
  ##############################################################################
  
  from openerp import models, api, _
  
  
  class SaleOrderLine(models.Model):
      _inherit = 'sale.order.line'
  
      @api.multi
      def button_save_data(self):
          return True
  
      @api.multi
      def button_details(self):
          context = self.env.context.copy()
          context['view_buttons'] = True
          view = {
              'name': _('Details'),
              'view_type': 'form',
              'view_mode': 'form',
              'res_model': 'sale.order.line',
              'view_id': False,
              'type': 'ir.actions.act_window',
              'target': 'new',
              'readonly': True,
              'res_id': self.id,
              'context': context
          }
          return view
  
subject: Return True