@NotNull
  public static Mutability getMutability(@NotNull PsiModifierListOwner owner) {
    if (owner instanceof LightElement) return UNKNOWN;
    return CachedValuesManager.getCachedValue(owner, () ->
      CachedValueProvider.Result.create(calcMutability(owner), owner, PsiModificationTracker.MODIFICATION_COUNT));
  }
@NotNull
  public static Mutability getMutability(@NotNull PsiModifierListOwner owner)