$ /home/docs/checkouts/readthedocs.org/user_builds/chainerui/envs/latest/bin/python -m pip install --exists-action=w --cache-dir /home/docs/checkouts/readthedocs.org/user_builds/chainerui/.cache/pip -r docs/requirements.txt
Collecting chainer>=3.0.0 (from -r docs/requirements.txt (line 1))
Using cached https://files.pythonhosted.org/packages/75/39/fa4ac5cf89179d76f7ba1f1897e5c1f2e4d0b89dd9f4e2b5e91b577bc5e1/chainer-6.0.0.tar.gz
Complete output from command python setup.py egg_info:
Traceback (most recent call last):
File "<string>", line 1, in <module>
File "/tmp/pip-install-WBQiIm/chainer/setup.py", line 192, in <module>
chainerx_build_helper.config_setup_kwargs(setup_kwargs, build_chainerx)
File "chainerx_build_helper.py", line 102, in config_setup_kwargs
'ChainerX is only available for Python 3.5 or later.')
RuntimeError: ChainerX is only available for Python 3.5 or later.
----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-install-WBQiIm/chainer/
https://readthedocs.org/projects/chainerui/builds/9082782/