I’m working on XML Digital Signature in InterSystems IRIS using %XML.Security.Signature

I start with an XML document that is created by parsing an input XML string, and I want to digitally sign this document using an X509 certificate.

Set##class%SYS.X

During signing, I got the below error:

Canonicalize error: Signature not found

From debugging, it appears that the signing process attempts to locate a <Signature> element in the XML document by its Id, but no such element exists at that point.

This leads to my main question:

Is it expected that XML doc already contains a <Signature>

I want to append items to the list inside a for loop

Example:

set$ListBuildfor

The output should be:

mylist = 

The code snippet written above is not working, looking for correct way to do it.