diff --git a/src/NodaHierarchyHelper.php b/src/NodaHierarchyHelper.php
index 5fa1e37..48bcc73 100644
--- a/src/NodaHierarchyHelper.php
+++ b/src/NodaHierarchyHelper.php
@@ -23,7 +23,7 @@ final class NodaHierarchyHelper {
     public static function findHighestRelatedTag(MDMysqli $mysqli_noda, int $tag_id, $higherStmt = null):int {
 
         $builtHigherStmt = false;
-        if (!$higherStmt instanceOf MDMysqliStmt) {
+        if (!$higherStmt instanceof MDMysqliStmt) {
             $higherStmt = $mysqli_noda->do_prepare("SELECT `tag_mayor_id`
                 FROM `tag_relation`
                 WHERE `tag_relation`.`tag_relation` != 2