docs: private static CmsXmlContentDefinition getCachedContentDefinition(String schemaLocation, EntityResolver resolver) {
  
          if (resolver instanceof CmsXmlEntityResolver) {
              // check for a cached version of this content definition
              CmsXmlEntityResolver cmsResolver = (CmsXmlEntityResolver)resolver;
              return cmsResolver.getCachedContentDefinition(schemaLocation);
          }
          return null;
      }