``` spec/document λ make all touch _build/.nojekyll cp -f index.html _build/ (cd core; make BUILDDIR=_build all) sphinx-build -b latex -d _build/doctrees -D latex_paper_size=a4 . _build/latex Running Sphinx v2.2.0 Extension error: Could not import extension mathdef (exception: cannot import name 'latex_visit_math') make[1]: *** [latexpdf] Error 2 make: *** [build-core] Error 2 ``` I could find the `mathdef.py` file under the repo <https://github.com/WebAssembly/funclets/blob/master/document/core/util/mathdef.py> but not sure how to fix this.