# File lib/aws/simple_db/attribute_collection.rb, line 114
      def each options = {}, &block
        yielded = {}
        each_value(options) do |attribute_name, attribute_value| 
          unless yielded[attribute_name]
            attribute = self[attribute_name]
            yield(attribute)
            yielded[attribute_name] = true
          end
        end
        nil
      end