@NotNull
    @Override
    public String parseValue(@Nullable String text) throws InvalidDataException {
      if (text == null) return "";
      StringBuilder result = new StringBuilder();
      for(String chunk : StringUtil.split(text, ",")) {
        String identifier = chunk.trim();
        if (!StringUtil.isEmpty(identifier)) {
          if (StringUtil.isJavaIdentifier(identifier)) {
            if (result.length() > 0) {
              result.append(',');
            }
            result.append(identifier);
          }
          else {
            throw new InvalidDataException("Identifier required");
          }
        }
      }
      return result.toString();
    }
@NotNull
    @Override
    public String parseValue(@Nullable String text)