@Override
  public @NotNull IntentionPreviewInfo generatePreview(@NotNull Project project, @NotNull ProblemDescriptor previewDescriptor) {
    PsiClass aClass = PsiTreeUtil.getParentOfType(previewDescriptor.getPsiElement(), PsiClass.class, false);
    if (aClass == null) return IntentionPreviewInfo.EMPTY;
    final PsiClass oldSuperClass = myOldSuperClass.getElement();
    final PsiClass newSuperClass = myNewSuperClass.getElement();
    if (oldSuperClass == null || newSuperClass == null) return IntentionPreviewInfo.EMPTY;
    addSuperClass(aClass, oldSuperClass, newSuperClass);
    return IntentionPreviewInfo.DIFF;
  }
@Override
  public @NotNull IntentionPreviewInfo generatePreview(@NotNull Project project, @NotNull ProblemDescriptor previewDescriptor)