code: @Override
      protected ServiceRegistration<D> addService(S service, ServiceProperties props) {
          D decorator = createDecorator(service, props);
          if (decorator == null) {
              return null;
          }
          Dictionary<String, ?> decoratorServiceProps = decoratorServiceProps(props);
          getLogger().info("Registering decorator service {} with properties {}", decoratorType.getSimpleName(), decoratorServiceProps);
          return getBundleContext().registerService(decoratorType, decorator, decoratorServiceProps);
      }
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