sagemathgh-39552: fix and activate the check for pep E272
    
and also cleaning the two modified files

### 📝 Checklist

- [x] The title is concise and informative.
- [x] The description explains in detail what this PR is about.
    
URL: sagemath#39552
Reported by: Frédéric Chapoton
Reviewer(s): David Coudert

Author: Release Manager