# File lib/aws/dynamo_db/batch_write.rb, line 187
      def convert_unprocessed_items items

        return nil if items.empty?

        request_items = {}

        items.each_pair do |table,requests|

          request_items[table] ||= []

          requests.each do |request|

            item = request.values.first

            request_items[table] <<
              case request.keys.first
              when 'PutRequest'    then convert_put_item(item['Item'])
              when 'DeleteRequest' then convert_delete_item(item['Key'])
              end

          end

        end

        request_items

      end