docs: public static final boolean isFolderType(String typeName) {
  
          try {
              return OpenCms.getResourceManager().getResourceType(typeName).isFolder();
          } catch (CmsLoaderException e) {
              throw new CmsIllegalArgumentException(
                  Messages.get().container(Messages.ERR_UNKNOWN_RESOURCE_TYPE_1, typeName),
                  e);
          }
      }