@NotNull
  static ChooseByNameItemProvider getItemProvider(@NotNull ChooseByNameModel model, @Nullable PsiElement context) {
    return model instanceof ChooseByNameModelEx ? ((ChooseByNameModelEx)model).getItemProvider(context)
                                                : new DefaultChooseByNameItemProvider(context);
  }
@NotNull
  static ChooseByNameItemProvider getItemProvider(@NotNull ChooseByNameModel model, @Nullable PsiElement context)