docs: public static ApplicationContext contextMergedBeans(Map<String, ?> extraBeans, Class<?> config) {
          final DefaultListableBeanFactory parentBeanFactory = buildListableBeanFactory(extraBeans);
          
          //loads the annotation classes and add definitions in the context
          GenericApplicationContext parentContext = new GenericApplicationContext(parentBeanFactory);
          AnnotatedBeanDefinitionReader annotationReader = new AnnotatedBeanDefinitionReader(parentContext);
          annotationReader.registerBean(config);
          
          //refreshed the context to create class and make autowires
          parentContext.refresh();
          
          //return the created context
          return parentContext;
      }