code: @SuppressWarnings("unchecked")
      public <T extends AbstractJaxb> void removeDescendants(String clazz,
              Class<T> tagType) {
          RemoveDescendantsUtil.removeDescendants((T) this, clazz, tagType);
      }
docs: <p>
  delete all descendant elements that is specified tag type having
  specified class attribute.
  </p>
  
  @param clazz
  class attribute
  @param tagType