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: external_document_subreport.rb
    path of file: ./repos/archivesspace/reports/custom
    
    the code of the file until where you have to start completion: class ExternalDocumentSubreport < AbstractSubreport

	register_subreport('exter
    
	def query_string
		"select
			title as record_title,
			location,
			publish,
			identifier_type_id as identifier_type
		from external_document
		where #{@id_type}_id = #{db.literal(@id)}"
	end