New Features
- Add initial value for product and sum on L ([406](https://github.com/fastai/fastcore/pull/406)), thanks to [radekosmulski](https://github.com/radekosmulski)
- add ppretty print repr to AttrDict ([403](https://github.com/fastai/fastcore/pull/403)), thanks to [hamelsmu](https://github.com/hamelsmu)
- Raise better error when a config isn't found ([394](https://github.com/fastai/fastcore/pull/394)), thanks to [muellerzr](https://github.com/muellerzr)
Bugs Squashed
- Bugfix handle edge case when we have string in list and want to flatten ([410](https://github.com/fastai/fastcore/pull/410)), thanks to [Salehbigdeli](https://github.com/Salehbigdeli)