Rails - Feb 2006 - Including a Module within a model

If I have a module with a callback in it:

module Sanitize
   module PhoneNumber
     def before_validation
       self.phone.gsub!(/\D/, '''') if
attribute_present?(''phone'')
     end
   end

   module MobileNumber
     def before_validation
       self.mobile.gsub!(/\D/, '''') if
attribute_present?(''mobile'')
     end
   end
end

and then I include that within my model:

class Contact < ActiveRecord::Base
   include Sanitize::PhoneNumber
end

Why doesn''t it work?? Any ideas?