extra.addAll(imports);
  private void genFactoryClassFile(ADT api) throws IOException {    class_name = api_factory;        info("generating " + class_name);        createClassStream(class_name);        genPackageDecl();        List extra = new LinkedList();    extra.add("aterm.pure.PureFactory");    genImports(extra);         genFactoryClass(api);        stream.close();  }