/**
     * Checks whether the given node has childs or it's relative_depth is > 0
     * @param eZContentObjectTreeNode $node
     * @return bool whether node is a hierarchy one
     */
    public static function isHierarchyNode( $node )
    {
        if ( $node instanceof eZContentObjectTreeNode === false )
        {
            return false;
        }

        //checking if node is a child node
        $solrDepthField = 'attr_relative_depth_i';
        $fq = "main_node_meta_node_id_si:{$node->MainNodeID}";

        $fields = array(
            $solrDepthField,
        );
        $solrResponse = SolrSafeOperatorHelper::getNodeSolrData($fq, $fields);
        if (is_array($solrResponse) && $solrResponse[0][$solrDepthField] > 0)
        {
            return true;
        }

        //checking if node is a parent node
        return $node->childrenCount() > 0;
    }