Python 3.5+ has type hints now (and a standalone typechecker). It doesn't do runtime checking by default, but you can use a 3rd party library to enforce these t

Python 3.5+ has type hints now (and a standalone typechecker). It doesn't do runtime checking by default, but you can use a 3rd party library to enforce these things if you are concerned about type safety (at the boundaries of your programs for checking inputs for example). More info on this in the pep: https://www.python.org/dev/peps/pep-0484/ https://www.python.org/dev/peps/pep-0484/