Error was thrown if FreeCADGui.Selection list had more than one item. Solution is to clear selection before adding selection from import operation. I also removed the `for` loop since the selection should be singular.
The class variable name was not corrected with previously committed changes.
The correct cutting edge variable name is located in the __init__() constructor method.
Fixes path generation for selection of two non-parallel edges.
Fixes path generation for selection of single, bottom face of slot with two non-parallel ends.
Fixes path generation for selection of two parallel, bottom bounding edges of slot.