@Override
  public String toString() {
    var result = new SmartList<String>();
    if (myAddedFileType != null) {
      result.add("added file type = " + myAddedFileType);
    }
    if (myRemovedFileType != null) {
      result.add("removed file type = " + myRemovedFileType);
    }

    return "FileTypeEvent[" + StringUtil.join(result, ", ") +  "]";
  }
@Override
  public String toString()