Here are a few possible enhancements in Extension Tutorial:
- Class names should be CamelCase (PEP8). todo and todolist are all-lowercase.
- In TodoDirective.run(), env.index_num seems to be an integer, but we interpolate it via "%s". It should be "%d".
If you guys think these minor details are important at all, I would be more than happy to create a patch or send you an appropriate pull request with the changes.