The reference number/ID of an agreement

retann_Required
No
retann_Examples
 <documentReference documentType="AgreementNumber" id="325899" date="2021-12-09"/> 
retann_Xpath
/b24Message/returnAnnouncement/documentReference[@documentType="AgreementNumber"]/@id
retann_Sort
2500
retann_Id
16
retann_Type
Text