[scikit-learn] Is there any official position on PEP484/mypy?

[Gael Varoquaux]

> * One relevant consequence is that, to add annotations on the code,
> scikit-learn should depend on the "typing"[1] module which contains some of the
> basic names imported and used in annotations. It's a stdlib module in python
> 3.5, but the PyPI package backports it to python 2.7 and newer (I'm not sure
> how it works with Python 2.6, which might be an issue)

I am afraid that this is going to be a problem: we have a no dependency
policy (beyond numpy and scipy).