This recipe only scratches the surface of the power of django-treebeard and its Materialized Path trees. There are many other methods available for navigation as well as construction of the trees. In addition, the API for Materialized Path trees is largely identical to those for Nested Sets trees and Adjacency List trees, which are available simply by implementing your model with the NS_Node or AL_Node abstract classes, respectively, instead of using MP_Node.
Read the django-treebeard API documentation for a complete listing of the available properties and methods for each of the tree implementations at https://django-treebeard.readthedocs.io/en/latest/api.html.