How can I install Python packages to the iruby Travis environment?

[kozo2]

I'm trying to automate checking

jupyter-nbconvert --to html --execute test/iruby/foo.ipynb

in https://github.com/kozo2/iruby/tree/travis-nbconvert

But I failed

• pip install nbconvert
• conda install nbconvert

in iruby .travis.yml

How can I install Python packages in https://github.com/SciRuby/iruby/blob/master/.travis.yml ?

[mrkn]

Could you do it in the docker container running on travis-ci?

[kozo2]

It seems that kozo2/iruby@c2cf55f
installs nbconvert to the docker container.
But I couldn't find a suitable place to run the nbconvert command.
Do you have any idea about this?