code: @Override
      public ILonePair removeLonePair(int position) {
          ILonePair lp = lonePairs[position];
          lp.removeListener(this);
          for (int i = position; i < lonePairCount - 1; i++) {
              lonePairs[i] = lonePairs[i + 1];
          }
          lonePairs[lonePairCount - 1] = null;
          lonePairCount--;
          notifyChanged();
          return lp;
      }
docs: {@inheritDoc}