lib/book.rb in book-0.0.1 vs lib/book.rb in book-0.1.0

@@ -1,3 +1,22 @@
-module Book
-  # Your code goes here...
+class Book < Structure
+  key      :edition
+  key      :format
+  key      :isbn
+  key      :pages,          :type => Integer
+  key      :publisher
+  key      :title
+  key      :volumes,        :type => Integer
+  key      :year_published, :type => Integer
+  has_many :authors
+  has_many :identifiers
+  has_many :images
+  has_many :other_editions
+
+  def isbn
+    identifier =
+      identifiers.detect { |identifier| identifier.name == 'ISBN-13' } ||
+      identifiers.detect { |identifier| identifier.name == 'ISBN-10' }
+
+    identifier ? identifier.value : nil
+  end
 end