code: protected function resolveNode($node) {
      if ( $node instanceof \Baum\Node ) return $node->reload();
  
      return $this->node->newNestedSetQuery()->find($node);
    }
docs: Resolves suplied node. Basically returns the node unchanged if
  supplied parameter is an instance of \Baum\Node. Otherwise it will try
  to find the node in the database.
  
  @param   \Baum\node|int
  @return  \Baum\Node