Update app.py

app.py

@@ -122,7 +122,7 @@ def _(create_download_button, json_form, save_file_name):
         json_form.value,
         filename_prefix=(
             save_file_name.value
-            if save_file_name.value
+            if save_file_name.value is not None
             else "downloaded_template_output"
         ),
     )