code: def update_last_activity(self, request, now):
          
          last_activity = get_last_activity(request.session)
          server_idle_for = (now - last_activity).seconds
  
          # Gracefully ignore non-integer values
          try:
              client_idle_for = int(request.GET['idleFor'])
          except ValueError:
              return
  
          # Disallow negative values, causes problems with delta calculation
          if client_idle_for < 0:
              client_idle_for = 0
  
          if client_idle_for < server_idle_for:
              # Client has more recent activity than we have in the session
              last_activity = now - timedelta(seconds=client_idle_for)
  
          # Update the session
          set_last_activity(request.session, last_activity)
docs: If ``request.GET['idleFor']`` is set, check if it refers to a more
          recent activity than ``request.session['_session_security']`` and
          update it in this case.