In Jupyter-book, I am creating a _toc.yml file. I have something like -

- caption: Tutorials
  chapters:
  - file: ../../notebooks/some_notebook

I get the exception -

home/code/nwb_datajoint/docs/web-doc/intro.md:: WARNING: toctree contains reference to nonexisting document '../../notebooks/some_notebook' [etoc.ref]
looking for now-outdated files... none found

How do I reference a relative directory in in _toc.yml's parent directory?