docs: private void filter(ValueSet filterValueSet, HashMap hashmap) {
          if (filterValueSet != null && hashmap != null && !filterValueSet.isEmpty() && !hashmap.isEmpty()) {
              Iterator it = filterValueSet.iterator();
              while (it.hasNext()) {
                  Object o = it.next();
                  if (hashmap.containsKey(o)) {
                      it.remove();
                  }
              }
          }
      }