diff --git a/classes/external/run_in_sandbox.php b/classes/external/run_in_sandbox.php
index a8c8826f..d73b429f 100644
--- a/classes/external/run_in_sandbox.php
+++ b/classes/external/run_in_sandbox.php
@@ -185,7 +185,7 @@ public static function execute(
                 $paramsarray['jobeserver'] = $jobehostws;
             }
             // usecache set to false for these runs as we will never regrade them.
-            $runresult = $sandbox->execute($sourcecode, $language, $stdin, $filesarray, $paramsarray, usecache:false);
+            $runresult = $sandbox->execute($sourcecode, $language, $stdin, $filesarray, $paramsarray, false);
         } catch (Exception $ex) {
             throw new qtype_coderunner_exception("Attempt to run job failed with error {$ex->message}");
         }