gh-36744: pep8 for maxima-lib interface
    
Just a full pep8 cleanup of the modified file.

### 📝 Checklist

- [x] The title is concise, informative, and self-explanatory.
- [x] The description explains in detail what this PR is about.
    
URL: #36744
Reported by: Frédéric Chapoton
Reviewer(s): Travis Scrimshaw

Author: Release Manager