private static DomExtensionImpl addExtension(final List<? super DomExtensionImpl> list, final @Nullable XmlName name, final Type type) {
    final DomExtensionImpl extension = new DomExtensionImpl(type, name);
    list.add(extension);
    return extension;
  }
private static DomExtensionImpl addExtension(final List<? super DomExtensionImpl> list, final @Nullable XmlName name, final Type type)