From our RL discussion: this code could be refactored into something *like* (but not necessarily)

```python
if self.show_mobile_worker_field:
    self.select_mobile_worker_field.update_context()
    select_mobile_worker_field = self.select_mobile_worker_field.context
    select_mobile_worker_field.update({
        'field': self.select_mobile_worker_field,
        'select': {
            'selected': [] if all_mws else filter(
                lambda s: s != '_all',
                select_mobile_worker_field["select"]["selected"]
            ),
            'options': select_mobile_worker_field["select"]["options"][1:]
        }
    })
...

context = {
    'select_mobile_worker_field': select_mobile_worker_field
}
```