code: public static <T> boolean isDescendantOfOrEqualTo(TreeDef.Parented<T> treeDef, T child, T parent) {
  		if (child.equals(parent)) {
  			return true;
  		} else {
  			return isDescendantOf(treeDef, child, parent);
  		}
  	}
docs: Returns true iff child is a descendant of parent, or if child is equal to parent.