code: private void loadSwaggerExtensions(ApiSource apiSource) throws GenerateException {
          if (apiSource.getSwaggerExtensions() != null) {
              List<SwaggerExtension> extensions = SwaggerExtensions.getExtensions();
              extensions.addAll(resolveSwaggerExtensions());
          }
      }
docs: The reader may modify the extensions list, therefore add the additional swagger extensions
  after the instantiation of the reader