code: public void addContextDataFactory(ContextDataFactory contextDataFactory) {
          if (contextDataFactories == null) {
              contextDataFactories = new ArrayList<>();
          }
          contextDataFactories.add(contextDataFactory);
      }
docs: Adds the given {@link ContextDataFactory} to the extension hook, to be later added to the {@link Model}.
  <p>
  By default, the {@code ContextDataFactory}s added are removed from the {@code Model} when the extension is unloaded.
  
  @param contextDataFactory the {@code ContextDataFactory} that will be added to the {@code Model}
  @since 2.5.0