public static void clearSlotFromClass(Symbol className, Symbol slotName) {
    className = ((Symbol)(className.permanentify()));
    slotName = ((Symbol)(slotName.permanentify()));
    { Surrogate renamed_Class = Logic.getDescription(className).surrogateValueInverse;
      List cases = Logic.allClassInstances(renamed_Class).listify();
      Surrogate slot = Logic.getDescription(slotName).surrogateValueInverse;

      { Stella_Object renamed_Case = null;
        Cons iter000 = cases.theConsList;

        for (;!(iter000 == Stella.NIL); iter000 = iter000.rest) {
          renamed_Case = iter000.value;
          Logic.smartUpdateProposition(Cons.cons(slotName, Cons.cons(renamed_Case, Cons.cons(LogicObject.getSlotValue(((LogicObject)(renamed_Case)), slot), Stella.NIL))), Logic.KWD_RETRACT_TRUE);
        }
      }
    }
  }