docs: public static CmsXmlContainerPage unmarshal(CmsObject cms, CmsResource resource) throws CmsException {
  
          // check the cache
          CmsXmlContainerPage content = getCache(cms, resource, true);
          if (content != null) {
              return content;
          }
  
          content = unmarshal(cms, cms.readFile(resource), true);
  
          // set the cache
          setCache(cms, content, true);
  
          return content;
      }