write() function of GlideSysAttachment() not working

[Saquib Mohammed]

I have written below script as a Scripted REST resouce in Global scope. However, the write function doesnt work

var queryParamsVar = request.queryParams;
var attachment = new GlideSysAttachment();
var correlationId = queryParamsVar.CorrelationId[0];
var grIncTask = new GlideRecord('incident_task');
grIncTask.addQuery('correlation_id', correlationId);
grIncTask.query();

var fileName = queryParamsVar.FileName[0];
var contentType = queryParamsVar.ContentType[0];
var base64Encodedcontent = queryParamsVar.Base64Enc[0];
var decodedBytes = GlideStringUtil.base64DecodeAsBytes(base64Encodedcontent);
var arg = attachment.write(grIncTask, fileName, contentType, decodedBytes);
gs.info('This is a log for attachment sys_id is: ' + agr);

In the system logs, I see the below error - 

*** Script: undefined: no thrown error

and

getEventTarget() called with invalid record reference: sys_poll. for event: appsec.security.export, could have been deleted

I was trying to use writeBase64 but later found that it can used only for scoped applications. So I tried with write function but this is not doing the job either.

[-O-]

Also note that in the original code you capture the output into variable

arg

but log variable

agr

Not sure if that is just a paste error, or the code is indeed faulty.