docs: public PartialConverter addPartialConverter(PartialConverter converter)
              throws SecurityException {
          
          checkAlterPartialConverters();
          if (converter == null) {
              return null;
          }
          PartialConverter[] removed = new PartialConverter[1];
          iPartialConverters = iPartialConverters.add(converter, removed);
          return removed[0];
      }