Readability and best practices | Type hinting for add_features in module 3 code

[Odessit007]

It seems to be a better practice to use generic type hints in such cases (it looks nicer and doesn't get notifications from some IDEs like PyCharm)

[alexeygrigorev]

This is a good PR, but I don't think it's a good idea to accept it - if I do, the code in the repo and in the videos will be different, and will be confusing for the students

[Odessit007]

That's a good point. Closing it.