code: def index(req, res):
      
      number = req.session.get('counter', -1)
      req.session['counter'] = int(number) + 1
      print(" -- Session '{id}' returned {counter} times".format(**req.session))
      msg = "Hello!! You've been here [[%s]] times" % (req.session['counter'])
      res.send_text(msg)
      req.session.save()
docs: Return root page of website.