private static void writeContentRoots(IonWriter writer, DomainObjectSet<? extends IdeaContentRoot> roots) throws IOException {
    writer.setFieldName("contentRoots");
    writer.stepIn(IonType.LIST);
    for (IdeaContentRoot contentRoot : roots) {
      writeContentRoot(writer, contentRoot);
    }
    writer.stepOut();
  }
private static void writeContentRoots(IonWriter writer, DomainObjectSet<? extends IdeaContentRoot> roots)