diff --git a/core b/core
index 692e8d6..efa734d 160000
--- a/core
+++ b/core
@@ -1 +1 @@
-Subproject commit 692e8d6e37697b9d841bc3bee0324064570877d7
+Subproject commit efa734da71fc253dad21e5012747325d42c7b2b9
diff --git a/ext/app/pipe/webworker.js b/ext/app/pipe/webworker.js
index 28b9e01..50425a5 100644
--- a/ext/app/pipe/webworker.js
+++ b/ext/app/pipe/webworker.js
@@ -83,8 +83,10 @@ function start(pyodidePromise) {
   addEventListener('message', async (e) => {
     if (e.data.type === 'call') {
       const { name, args } = e.data;
-      const result = (await pyodidePromise).globals.get("call")(name, args);
-      const data = result?.toJs({ dict_converter: Object.fromEntries });
+      let data = (await pyodidePromise).globals.get("call")(name, args);
+      if (data?.toJs) {
+        data = data.toJs({ dict_converter: Object.fromEntries });
+      }
       postMessage({ type: 'data', data });
     }
   });