[scikit-learn] Difference between CircleCI python2 and python3

[Oliver Rausch]

Hi all,

I'm working on a PR [1] and the Circle python2 build [2] doesn't
complete, while the python3 build does. Locally, building using "make
html" also works. What is the difference between these two builds, and
how could I locally debug the issue?

Thanks,
Oliver

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[1] https://github.com/scikit-learn/scikit-learn/pull/11682
[2] https://circleci.com/gh/scikit-learn/scikit-learn/38492