elasticsearch_dsl filter out data in a field containing a specific character

Question

I have a dataset containing windows event logs, I am trying to filter out values in a field TargetUserName that contain a specific character of say #.

basically, if TargetUserName contains # do not aggregate it. Below is my current code.

    es = Elasticsearch([localhostmines], timeout=30)
    s = Search(using=es, index="logindex-*").filter('term', EventID="4624").filter('term', TargetUserName="*#")

    users = set([])
    for hit in s.scan():
        users.add(hit.TargetUserName)

    print(users)

Any help would be greatly appreciated. Thank you.