What you need to get this example running.

First, you will need to install the pygal package and the world maps module
for pygal.

To do this, open a terminal window on Mac or the Anaconda Prompt on Windows
and execute these commands:

pip install pygal
pip install pygal_maps_world

Next, make sure that you use the updated version of the source code I have
provided here. The updates in the source code come from the author's errata
for chapter 16 available at

https://ehmatthes.github.io/pcc/chapter_16/README.html