sort_libraries_updated.rb

class Book
  include AttributesSort
  attr_accessor :author, :date
  
  def initialize(author, date)
    @author = author
    @date = date
  end
end
 
def sort_libraries(libraries, key)
  return libraries.map do |library|
    library.attr_sort(:sort_by => key)
  end
end
  
  
bobs_books = [Book.new("doe", Time.now + 5000000), Book.new("ajay", Time.now), Book.new("johnson", Time.now + 2592000)]
marys_books = [Book.new("jackson", Time.now + 3000000), Book.new("coe", Time.now), Book.new("coe", Time.now + 2592000)]
toms_books = [Book.new("lola", Time.now + 2000000), Book.new("loe", Time.now), Book.new("black", Time.now + 2592000)]
  
sorted_libraries = sort_libraries([bobs_books,marys_books,toms_books],[:author,:date])

require 'pp'
pp bobs_books.attr_sort(:sort_by => [:author,:date])
puts
pp marys_books.attr_sort(:sort_by => [:author,:date])
puts
pp toms_books.attr_sort(:sort_by => [:author,:date])
puts
puts

pp sorted_libraries