Selecting python-flask vs python3-flask

[Mathieu Malaterre <mathieu.malaterre@gmail.com>]

[CC me please]

Hi,

  I am trying to work on :

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=740907

  Basically I have an example package (dh_installexamples) which needs
to depends on python-flask. Depending whether my users installed
python3-openslide or python-openslide, I need to Recommends on
python3-flask or (exclusive) python-flask.

  I have not figure out how to do that. I could not find anything like
this in the doc.

Thanks for help,
-- 
Mathieu