code: private static List<String> parseTagNames(String tagNames) {
      return Arrays.stream(tagNames.split("\\s*,\\s*"))
          .map(String::trim)
          .collect(Collectors.toList());
    }
docs: Parses a comma separated list of tag names.
  
  @param tagNames a comma separated list of tag names.
  @return the list of tag names.