docs: private static void parseStencilSet(JSONObject modelJSON,
                                          Diagram current) throws JSONException {
          // get stencil type
          if (modelJSON.has("stencilset")) {
              JSONObject object = modelJSON.getJSONObject("stencilset");
              String url = null;
              String namespace = null;
  
              if (object.has("url")) {
                  url = object.getString("url");
              }
  
              if (object.has("namespace")) {
                  namespace = object.getString("namespace");
              }
  
              current.setStencilset(new StencilSet(url,
                                                   namespace));
          }
      }