Static types in Python, oh my(py)!

The exciting news is that over the last year, a team at Dropbox (including Python creator Guido van Rossum!) has led the development of mypy into a mature type checker that can enforce static type consistency in Python programs. For the many programmers who work in large Python 2 codebases, the even more exciting news is that mypy has full support for type-checking Python 2 programs, scales to large Python codebases, and can substantially simplify the upgrade to Python 3.