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: german_details_converter.rb
    path of file: ./repos/ibandit/lib/ibandit
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

# German bank details don't map directly to IBANs in the same way as in other
# countries - each bank has idiosyncracies for translating its cusomers' bank
# details. These idiosyncracies are described in a document from the Bundesbank:
# https://www.bundesbank.de/Redaktion/EN/Standardartikel/Tasks/Payment_systems/iban_rules.html?nn=26102

module Ibandi
    
      def converted_details
        updated_account_number =
          case @account_number.to_i
          when 100000..899999 then @account_number + "000"
          when 30000000..59999999 then @account_number
          when 100000000..899999999 then @account_number
          when 1000000000..1999999999 then @account_number
          when 3000000000..7099999999 then @account_number
          when 8500000000..8599999999 then @account_number
          when 9000000000..9999999999 then @account_number
          else disallow
          end