docs: def next_redirect(request, fallback, **get_kwargs):
      """
      Handle the "where should I go next?" part of comment views.
  
      The next value could be a
      ``?next=...`` GET arg or the URL of a given view (``fallback``). See
      the view modules for examples.
  
      Returns an ``HttpResponseRedirect``.
      """
      next = request.POST.get('next')
      if not is_safe_url(url=next, allowed_hosts=request.get_host()):
          next = resolve_url(fallback)
  
      if get_kwargs:
          if '#' in next:
              tmp = next.rsplit('#', 1)
              next = tmp[0]
              anchor = '#' + tmp[1]
          else:
              anchor = ''
  
          joiner = ('?' in next) and '&' or '?'
          next += joiner + urlencode(get_kwargs) + anchor
      return HttpResponseRedirect(next)