Now that we can understand the C++-oriented documentation, let's see how the PyQGIS libraries are structured. All of the PyQGIS libraries are organized under a package named qgis. You wouldn't normally import qgis directly, however, as all the interesting libraries are subpackages within this main package; here are the five packages that make up the PyQGIS library:

The first two packages (qgis.core and qgis.gui) implement the most important parts of the PyQGIS library, and it's worth spending...