docs: def switch_state(request):
      """
      Switch the default version state in
      the session.
      """
  
      if request.session.get(SESSION_KEY):
          request.session[SESSION_KEY] = False
      else:
          request.session[SESSION_KEY] = True
  
      # Get redirect location
      # Don't go to non local paths
      url = request.GET.get('redirect_to', '/')
      if url.startswith('http'):
          url = '/'
      return redirect(url)