When e.g. executing `drawing.strokes[0].softness = 3`, the API would always create a new attribute `softness` even if that attribute existed already. The issue was that the code was using the `.get(value, fallback)` syntax but the `fallback` expression is always evaluated by python. The fix removes the use of the `fallback` and uses a simple `if/else` to check if the attribute doesn't exist yet and only then create it. Pull Request: https://projects.blender.org/blender/blender/pulls/129044