You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: order_merge.rb
    path of file: ./repos/workarea/core/app/services/workarea
    
    the code of the file until where you have to start completion: module Workarea
  class OrderMerge
    attr_reader :original

    def initialize(original)
      @original = original
    end

    def merge(other)
      return unless original.valid?

      other.items.each do |item|
       
    
    def merge(other)
      return unless original.valid?

      other.items.each do |item|
        next if original.has_sku?(item.sku)

        attributes = OrderItemDetails.find!(item.sku, product_id: item.product_id).to_h

        original.add_item(
          attributes.merge(
            product_id: item.product_id,
            sku: item.sku,
            quantity: item.quantity,
            customizations: item.customizations
          )
        )
      end

      other.promo_codes.each do |code|
        original.add_promo_code(code)
      end

      original.save!
    end