Inside the class `_DraftLink` the `onDocumentRestored` function tests for the existence of the old attribute `useLink`. If it is present, it uses it to define the new variable name `use_link`. This is done use Python naming conventions. The old `useLink` is deleted so it is not longer saved together with the object when the document is saved.
2020 February
These files provide the logic behind the task panel of the GuiCommands
defined in draftguitools/.
The task panel graphical interface is properly defined in
the Resources/ui/ files, which are made with QtCreator.
There are many commands which aren't defined in draftguitools/.
These are defined in the big DraftGui.py module, which needs to be split
into individual GuiCommands, and each should have its own dedicated
.ui file.