docs: private String clean(final Collection<String> values) {
      if (values == null || values.size() == 0) {
        return "";
      }
  
      final List<String> strs = Lists.newArrayList();
      for (String v : values) {
        final String tmp = v.replaceAll("\\{.*\\}", "");
        final int ix = tmp.lastIndexOf(':');
        if (ix < 0) {
          strs.add(tmp);
        } else {
          strs.add(tmp.substring(ix+1));
        }
      }
  
      return DOUBLE_COMMA_JOINER.join(strs);
    }