For some time now, Python has had the ability to “annotate” names with type information, in one form or another. With Python 3.5, type hints officially became part of the language (PEP 484).

Defining a list in Python is easy—just use the bracket syntax to indicate items in a list, like this: list_of_ints = [1, 2, 3] Items in a list do not have to all be the same type; they can be ...

You can read more about the origins of type annotations in Python, and how to use them, in PEP (Python enhancement proposal) 484, available online here. Reuven Lerner teaches Python, data science and ...