docs: @SuppressWarnings( "unchecked" )
      public <ValueType> List<ValueType> getPropertyAsList( Property propertyId,
                                                            Class<ValueType> type ) {
          if (nodeProperties == null) return null;
          Object property = nodeProperties.get(propertyId);
          if (property instanceof List) {
              return (List<ValueType>)property;
          }
          if (property == null) return null;
          List<ValueType> result = new ArrayList<ValueType>();
          result.add((ValueType)property);
          return result;
      }