This is the father of all classes handled by the document addProperty(string, string) -- Add a generic property. The first argument specifies the type, the second the name of the property. removeProperty(string) -- Remove a generic property. Note, you can only remove user-defined properties but not built-in ones. A list of supported property types Mark the object as changed (touched) Mark the object as unchanged Register an expression for a property Recomputes this object A list of all objects this object links to. A list of all objects which link to this object. Return the internal name of this object Return the document this object is part of State of the object in the document If the GUI is loaded the associated view provider is returned or None if the GUI is not up