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: export_helpers.rb
    path of file: ./repos/archivesspace/backend/app/exporters/lib
    
    the code of the file until where you have to start completion: module ASpaceExport
  # Convenience methods that will work for resource
  # or archival_object models during serialization
  module ArchivalObjectDescriptionHelpers

    def archdesc_note_types
      %w(accruals appraisal arrangement bioghist accessrestrict legalstatus userestrict custodhist altformavail originalsloc fileplan odd acqinfo otherfindaid phystech prefercite processinfo relatedmaterial scopecontent separatedmaterial)
    end


    
    
    def archdesc_dates
      unless @archdesc_dates
        results = []
        dates = self.dates || []
        dates.each do |date|
          normal = ""
          unless date['begin'].nil?
            normal = "#{date['begin']}/"
            normal_suffix = (date['date_type'] == 'single' || date['end'].nil? || date['end'] == date['begin']) ? date['begin'] : date['end']
            normal += normal_suffix ? normal_suffix : ""
          end
          type = ( date['date_type'] == 'inclusive' ) ? 'inclusive' : ( ( date['date_type'] == 'single') ? nil : 'bulk')
          content = if date['expression']
                      date['expression']
                    elsif date['end'].nil? || date['end'] == date['begin']
                      date['begin']
                    else
                      "#{date['begin']}-#{date['end']}"
                    end