Get issue id of last created issue, and check issue type

[-]

Referencing the round robin assignment script from adaptavist library:https://library.adaptavist.com/entity/round-robin-assign-issue-to-users-in-a-certain-project-role, I want to get the last issue created in a project, but i also want to focus in on a certain issue type. 

Here's what I changed in the script:

def lastIssueIdWithAssignee = issueManager.getIssueIdsForProject(issue.projectObject.id)
.sort()
.reverse()
.find {issue.getAsString("issuetype") == "Certification" }

So with this, I thought I'd be able to find the last Certification issue created in that project, but this doesn't seem to be the case...because the assignee keeps defaulting to the first user listed in the user key array.

Is there anything wrong with the change I made to the script?