Type annotations and mypy #4698
Description
🚀 Feature
Introduce mypy in pre-commit pipeline
Motivation
Static type checking is an interesting and powerful technique to assure high code quality and standard. I believe it should be unvaluable to start introducing type annotation and add mypy among pre-commit hooks
Pitch
I want to check the correctness of types annotation with a static type checking. When I commit, the checker should verify and eventually notify the contributer to check his code
Alternatives
Additional context
I ran mypy onto tests and it heighights some deprecated calls (such as checkpoint_callback, now in callbacks list). These checks could be useful to static check tests and find avoid obsolescent tests