principaluri === 'principals/' . $user->email; } public function update(User $user, Book $book): bool { return $book->principaluri === 'principals/' . $user->email; } public function delete(User $user, Book $book): bool { return $book->principaluri === 'principals/' . $user->email; } public function share(User $user, Book $book): bool { // Placeholder for future sharing logic return $book->principaluri === 'principals/' . $user->email; } }