code: public function isSelfOrAncestorOf($other) {
     return (
        $this->getLeft() <= $other->getLeft() &&
        $this->getRight() > $other->getLeft() &&
        $this->inSameScope($other)
      );
    }
docs: Returns true if node is self or an ancestor.
  
  @param NestedSet
  @return boolean