docs: def _netid_category_url(netid, category_codes):
      """
      Return UWNetId resource for provided netid and category
      code or code list
      """
      return "{0}/{1}/category/{2}".format(
          url_base(), netid,
          (','.join([str(n) for n in category_codes])
           if isinstance(category_codes, (list, tuple))
           else category_codes))