Add typing annotations about pipenv HOT 4 OPEN

Hey @Kroppeb -- sorry I've been away for a bit the start of this year, but I am getting back into pipenv issues now. There isn't a real reason we are lacking type annotations other than the pile of technical debt we are chipping away at -- not so long ago pip-shims and requirementslib/vistir were all part of the equation too but not anymore. We would welcome any community driven PR enhancements that solve problems and/or further help cleanup the codebase. You can find me hanging out in the Python Developers slack group, I am not sure if this invite will work but you can definitely find it or email me -- its on my github profile. https://join.slack.com/t/pythondev/shared_invite/zt-2fcjlo1yc-NisCSxAbN7BT~cP9PKpD6w

from pipenv.

@matteius Do you want the types as type annotations, or do you think it's better to specify the types in the docstrings to avoid circular imports?

from pipenv.

I'd prefer type annotations over docstrings -- its more modern and useful in general. I think circular imports can be avoided because you can do you can string quote types we provide that would be a circular import. Like -> "PipFile" (probably not a real example, but for clarity). Also, if we are returning types in a way that create a circular import, longer term we should try refactoring how that code is organized better.

from pipenv.

Good to know, I'll probably make a pr then one of the next few days

from pipenv.