diff --git a/lib/table/assignsubmissiontablemerger.php b/lib/table/assignsubmissiontablemerger.php
index 0736e0b..8a758c2 100644
--- a/lib/table/assignsubmissiontablemerger.php
+++ b/lib/table/assignsubmissiontablemerger.php
@@ -27,6 +27,7 @@
 class AssignSubmissionTableMerger extends GenericTableMerger {
 
     private $findassignsubmissions;
+    private $duplicateddatamerger;
 
     public function __construct() {
         parent::__construct(new AssignSubmissionDuplicatedDataMerger());