@NotNull
  public static Collection<PsiClass> collectInnerClassesIntern(@NotNull PsiClass psiClass) {
    if (psiClass instanceof PsiExtensibleClass) {
      return ((PsiExtensibleClass) psiClass).getOwnInnerClasses();
    } else {
      return filterPsiElements(psiClass, PsiClass.class);
    }
  }
@NotNull
  public static Collection<PsiClass> collectInnerClassesIntern(@NotNull PsiClass psiClass)