Using jupyter book with Sage Math

[BruceWestbury]

I am having trouble getting started with my jupyter book. I started with just markdown (no notebooks and no code-cells) and everything works as expected. I then tried including code-cell and then using existing notebooks. Neither of these has worked for me. My notebooks use a SageMath kernel and work without any problem. I feel I am missing something basic.

Here is the context:

$ jupyter --version
Selected Jupyter core packages...
IPython : 8.4.0
ipykernel : 6.14.0
ipywidgets : not installed
jupyter_client : 7.3.4
jupyter_core : 4.10.0
jupyter_server : 1.17.1
jupyterlab : not installed
nbclient : 0.5.13
nbconvert : 6.5.0
nbformat : 5.4.0
notebook : 6.4.12
qtconsole : not installed
traitlets : 5.2.2

$ jupyter kernelspec list
Available kernels:
python3 /home/bruce/.local/share/jupyter/kernels/python3
sagemath-dev /home/bruce/.local/share/jupyter/kernels/sagemath-dev

The sagemath-dev kernel is a symbolic link to a file in the sage folder. This works with the Jupyter notebook.

This is the relevant part of what I get from trying to build my book with a code-cell:

WARNING: Found an unexpected code-cell or raw-cell directive. Either this file was not converted to a notebook, because Jupytext header content was missing, or the code-cell was not converted, because it is nested. See https://myst-nb.readthedocs.io/en/latest/use/markdown.html for more information. [mystnb.nbcell]

I have not nested code-cells. So this tells me that Jupytext header content was missing. I haven't been able to find out from the documentation what header content is needed and where to put it.

Could some kind person please tell me what I am missing?

[BruceWestbury]

I have got it to work. I paired a notebook with MyST and that worked. Then I did a cut and paste from the top of the markdown into my markdown file. Then that worked with a code-cell. Fingers crossed; I am good to go!