I don't think this will work (I guess you could put a breakpoint in it and see if it's getting called). The way to use this is the following pattern; however, in this case, I don't see any patches anyway; so, I think all of the patch.stopall() calls in here are useless:
```
        datetime_patcher = patch.object(openassessmentblock, 'dt', Mock(wraps=dt))
        mocked_datetime = datetime_patcher.start()
        self.addCleanup(datetime_patcher.stop)
```
That is, provide a function to call as the clean up right after creating the patch.