this derivation will be built:
  /nix/store/jzhy64ksc87fvpq7kzhl6s2jwln4xkm3-spec-nbstripout.drv
building '/nix/store/jzhy64ksc87fvpq7kzhl6s2jwln4xkm3-spec-nbstripout.drv' on 'grpc://farm.numtide.com:50051?client-cert=/run/secrets/vars/per-machine/bld1/nix-farm-ci/crt&client-key=/run/secrets/vars/per-machine/bld1/nix-farm-ci/key&connect-timeout=20&system=aarch64-linux'
building '/nix/store/jzhy64ksc87fvpq7kzhl6s2jwln4xkm3-spec-nbstripout.drv' on farm.numtide.com:50051
spec-nbstripout> elastic-arm-234f8218: building jzhy64ksc87fvpq7kzhl6s2jwln4xkm3-spec-nbstripout.drv
spec-nbstripout> /nix/store/mkbzf98d1n5lxa1jsxfp2jmbfhy5gv7l-python3.14-nbformat-5.10.4/lib/python3.14/site-packages/nbformat/__init__.py:96: MissingIDFieldWarning: Cell is missing an id field, this will become a hard error in future nbformat versions. You may want to use `normalize()` on your notebooks before validations (available since nbformat 5.1.4). Previous versions of nbformat are fixing this issue transparently, and will stop doing so in the future.
spec-nbstripout>   validate(nb)
spec-nbstripout> /nix/store/mkbzf98d1n5lxa1jsxfp2jmbfhy5gv7l-python3.14-nbformat-5.10.4/lib/python3.14/site-packages/nbformat/__init__.py:96: MissingIDFieldWarning: Cell is missing an id field, this will become a hard error in future nbformat versions. You may want to use `normalize()` on your notebooks before validations (available since nbformat 5.1.4). Previous versions of nbformat are fixing this issue transparently, and will stop doing so in the future.
spec-nbstripout>   validate(nb)
spec-nbstripout> No valid notebook detected in 'invalid/a.ipynb'
spec-nbstripout> No valid notebook detected in 'invalid/a.ipynb'

upload niks3: ok