protected function isTrueForBook(Book $book) { if ($this->isEasy()) { return $book->isEasy(); } if ($this->isNormal()) { return $book->isNormal(); } if ($this->isHard()) { return $book->isHard(); } }
protected function isTrueForBook(Book $book) { return mb_strlen($book->getTitle()) > $this->threshold; }