door lever/knob

My cats learned how to open garage doors. I installed door lever upright, but they learned how to open it too. So I designed this knob. It is for "Europeans" style door levers. Original part costs about 15€. Hole is for circa 7 mm shaft. Hole for screw need to be drilled for your needs. Need to be little smaller than screw. (WB brand door lever) designed in tinkercad, sliced with 5 perimeters.