[Debian-astro-maintainers] Bug#950144: imexam FTBFS with astropy 4.0

[Adrian Bunk]

Source: imexam
Version: 0.8.1-1
Severity: serious
Tags: ftbfs

https://tests.reproducible-builds.org/debian/rb-pkg/unstable/amd64/imexam.html

...
Running Sphinx v1.8.5
/usr/lib/python3/dist-packages/astropy/config/configuration.py:557: ConfigurationMissingWarning: Configuration defaults will be used due to FileNotFoundError:2 on None
  warn(ConfigurationMissingWarning(msg))

Configuration error:
There is a programmable error in your configuration file:

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/sphinx/config.py", line 368, in eval_config_file
    execfile_(filename, namespace)
  File "/usr/lib/python3/dist-packages/sphinx/util/pycompat.py", line 150, in execfile_
    exec_(code, _globals)
  File "/build/1st/imexam-0.8.1/docs/conf.py", line 43, in <module>
    from astropy.extern import six
ImportError: cannot import name 'six' from 'astropy.extern' (/usr/lib/python3/dist-packages/astropy/extern/__init__.py)
...
Sphinx Documentation subprocess failed with return code 2
make[1]: *** [debian/rules:19: override_dh_installdocs-indep] Error 2