class Book
 class Book_1 
    def initialize (title, author, year)
      title = "Война и мир"
      author = "Лев  Толстой"
      year = "1869"
      is_available = true
      to_s = "ID: [id], [title] ([author], [year]) - [Доступна/Выдана]"
      
  end

  class Book_2
    def initialize (title, author, year)
      title = "Мастер и маргарита"
      author = "Михаил Булгаков"
      year = "1967"
      is_available = false
      to_s = "ID: [id], [title] ([author], [year]) - [Доступна/Выдана]"
    end
 
  end
  end

end