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: original_payment.rb
    path of file: ./repos/spree/core/app/models/spree/reimbursement_type
    
    the code of the file until where you have to start completion: class Spree::ReimbursementType::OriginalPayment < Spree::ReimbursementType
  extend Spree::ReimbursementType::ReimbursementHelpers


    
    def reimburse(reimbursement, return_items, simulate)
      unpaid_amount = return_items.map { |ri| ri.total.to_d.round(2) }.sum
      payments = reimbursement.order.payments.completed

      reimbursement_list, unpaid_amount = create_refunds(reimbursement, payments, unpaid_amount, simulate)
      reimbursement_list
    end