docs: def pagination_for(context, current_page, page_var="page", exclude_vars=""):
      """
      Include the pagination template and data for persisting querystring
      in pagination links. Can also contain a comma separated string of
      var names in the current querystring to exclude from the pagination
      links, via the ``exclude_vars`` arg.
      """
      querystring = context["request"].GET.copy()
      exclude_vars = [v for v in exclude_vars.split(",") if v] + [page_var]
      for exclude_var in exclude_vars:
          if exclude_var in querystring:
              del querystring[exclude_var]
      querystring = querystring.urlencode()
      return {
          "current_page": current_page,
          "querystring": querystring,
          "page_var": page_var,
      }