filling in the helper function bits + using "html_safe" method since I am on Rails 3

cookbook/015/hodgepodge/app/helpers/list_helper.rb

@@ -1,2 +1,9 @@
+require 'sha1'
+
+
 module ListHelper
+  def create_li(item, i)
+    %{<li class="#{ i % 2 == 0 ? 'even' : 'odd' }">#{i}:
+        #{SHA1.new(item.object_id.to_s)}</li>}
+  end
 end