Ok, it's just, i didn't see inherited classes from ```SubmissionRule``` which have a different definition:

 - In ```SubmissionRule```, the definition is ```def commit_after_collection_message```
 - In ```NoLateSubmissionRule < SubmissionRule``` (for example), the definition is ```def after_collection_message(grouping)```

But what my IDE said was that no one used the ```grouping``` argument.