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: reimbursement_type_engine.rb
    path of file: ./repos/spree/core/app/models/spree/reimbursement
    
    the code of the file until where you have to start completion: module Spree
  class Reimbursement::ReimbursementTypeEngine
    include Spree::R
    
    def calculate_reimbursement_types
      @return_items.each do |return_item|
        reimbursement_type = calculate_reimbursement_type(return_item)
        @reimbursement_type_hash[reimbursement_type] << return_item if reimbursement_type
      end

      @reimbursement_type_hash
    end