Creating native Python extensions with PyO3

In this section, we'll see how Python can also call Rust code. The Python community has always been a heavy user of native modules such as numpy, lxml, opencv, and so on, and most of them have their underlying implementations in either C or C++. Having Rust as an alternative to native C/C++ modules is a major advantage both in terms of speed and safety for a lot of Python projects out there. For the demo, we'll build a native Python module that's implemented in Rust. We'll be using pyo3, a popular project that provides Rust bindings for the Python interpreter and hides all the low-level details, thus providing a very intuitive API. The project is on GitHub at https://github.com/PyO3/pyo3. It supports both Python 2 and Python 3 versions. pyo3 is a fast-moving target and only works on nightly at the time of writing...