Quite a few middleware-related python objects don't have a useful string representation. I've listed the ones I know about below, with suggestions for how to implement stringification.
- FilterDefinitions: repr could duplicate str?
- Pipeline: the str could be the instrument and description fields?
- Butler: at minimum, repr should match str.
- Registry: repr almost looks more useful to me; str is just a long string with the path.
- Datastore: str/repr exist, but could be more useful.
- StorageClassFactory: repr could duplicate str?