code: protected void removeItem(int item, int bin) throws ContradictionException {
          updateLoads(item, bin);
          if (decoKPSimple != null) {
              decoKPSimple.postRemoveItem(item, bin);
          }
      }
docs: apply rule 2 (binLoad <= binPotentialLoad) when an item has been removed from the bin candidate list
  
  @throws ContradictionException if a contradiction (rule 2) is raised