"F841 local variable unused" triggering erroniously

Example code below:

```
    # Verify the annotation is coming from two different sources
    annotations = get_annotations(tdm_client, node_uid)

    assert len({annotations["source_uid"] for annotations in annotations}) == 2
```

This is triggering for me

```
.../.../test_annotation_filter.py:352:5: F841 Local variable `annotations` is assigned to but never used
```