Create a wringing deformation. Wringing is similar to twisting, but with a variable angle progression. If an input shape is provided, it will be deformed accordingly.

Input parameters:

1. Sh → Optional shape to wring.
2. Pl → Orientation plane. The wringing axis is coincident with the plane z-axis.
3. An → Function describing the wringing angle based on distance to plane.
4. Dg → If true, the function values represent angles measured in degrees instead of radians.

Output parameters:

1. Sh → Shape with applied deformation.
2. Df → Wringing deformation.