Python’s recently added type hinting system doesn’t really help here, either. It’s only intended to be used as an ahead-of-time linting tool, not a compile-time or runtime optimization tool.

Python 3 introduced the idea of "type annotations," and as of Python 3.6, you can annotate variables, not just function parameters and return values. The idea is that you can put a colon (:) and then ...

The new iteration support in Python works seamlessly with Python sequences but now also allows programmers to iterate through nonsequence types, including user-defined objects. An additional benefit ...