old_contents: # -*- coding: utf-8 -*-
  
  from basehandler import BaseHandler
  
  
  class Logout(BaseHandler):
      def get(self, pre):
          self.logout()
          self.redirect(pre)
  
new_contents: # -*- coding: utf-8 -*-
  
  from basehandler import BaseHandler
  
  
  class Logout(BaseHandler):
      def get(self):
          self.logout()
          self.redirect('/')
  
subject: Fix bug