No error is raised. playground.py opens as a plain Python file with
# %% markers instead of notebook cells. Playgrounds use jupytext
percent format: one .py file that behaves as a notebook in the right
editor.
Fix
- VS Code: install the Python extension, then open
playground.py
and use Run Cell / the interactive window. VS Code understands
# %% natively.
- JupyterLab: enable the jupytext contents manager so percent-format
files open as notebooks.
- Committed an
.ipynb by accident: the repo keeps playgrounds as
percent-format Python. In a repository checkout, run bake nb-to-py
to convert everything back and delete the .ipynb files.
How the playground is meant to be used is covered in
Notebooks.
Not this problem? Every fix lives on
Troubleshooting. Last modified on August 31, 2026
