fix runtime err

app.py

@@ -128,7 +128,7 @@ generator = gr.Interface(
             info="QR Code Content or URL",
             value="",
         ),
-        qr_code_image = gr.Image(
+        gr.Image(
             label="QR Code Image (Optional). Leave blank to automatically generate QR code",
             type="pil",
         ),
@@ -334,4 +334,5 @@ generator = gr.Interface(
 # blocks.queue(concurrency_count=1, max_size=20)
 # blocks.launch(share=bool(os.environ.get("SHARE", False)))
 if __name__ == "__main__":
-    demo.launch()
+    generator.queue(concurrency_count=1, max_size=20)
+    generator.launch()