@Nullable
  private static PsiElement smartAdvance(PsiElement element, boolean fwd) {
    final PsiElement candidate = getSiblings(element, fwd).filter(e -> isFlippable(e)).first();
    if (candidate != null && isBrace(candidate)) return null;
    return candidate;
  }
@Nullable
  private static PsiElement smartAdvance(PsiElement element, boolean fwd)