code: public Set<? extends AbstractBean<?, ?>> resolveSpecializedBeans(Bean<?> specializingBean) {
          if (specializingBean instanceof AbstractClassBean<?>) {
              AbstractClassBean<?> abstractClassBean = (AbstractClassBean<?>) specializingBean;
              if (abstractClassBean.isSpecializing()) {
                  return specializedBeans.getValue(specializingBean);
              }
          }
          if (specializingBean instanceof ProducerMethod<?, ?>) {
              ProducerMethod<?, ?> producerMethod = (ProducerMethod<?, ?>) specializingBean;
              if (producerMethod.isSpecializing()) {
                  return specializedBeans.getValue(specializingBean);
              }
          }
          return Collections.emptySet();
      }
docs: Returns a set of beans specialized by this bean. An empty set is returned if this bean does not specialize another beans.