Translations:Manual:Creating parametric objects/7/en

All Python classes usually have an __init__ method. What is inside that method is executed when that class is instantiated (which means, in programming slang, that a Python Object is created from that class. Think of a class as a "template" to create live copies of it). In our __init__ function here, we do two important things: 1) store our class itself into the "Proxy" attribute of our FreeCAD documetn object, that is, the FreeCAD document object will carry this code, inside itself, and 2) create all the properties our object needs. There are many types of properties available, you can get the full list by typing this code: