We briefly touched on importing modules way back in Chapter 1, The Fundamentals of Python. Modules are also called libraries or packages. Modules are modular, often self-contained Python programs that are commonly utilized in other programs, hence the need to import them for access.
Modules are used to separate code to make a program easier to work with, as each module can be designed to do one thing well, rather than having to make a single program that is responsible for all logic.
The Python Package Index (PyPI) website (https://pypi.org) is the official repository of third-party Python libraries. At the time of writing, there are more than 150,000 packages available for download from PyPI. Most of these packages are designed to be imported into a Python project to provide additional, or easier, functionality than can be achieved with the default Python libraries.