The pungi RPM requires both Python 2 and Python 3.
Except in very special circumstances, there is no need for one package
to drag in both Python stacks. Usually, this is a packaging error: for
example, a stray "/usr/bin/python" shebang in a Python 3 package can
introduce a Python 2 dependency.
Please split your package, or remove the stray dependencies.
There is a section on shebangs in the Python RPM Porting Guide 
which covers this issue.
It's ok to do this in Rawhide only, however, it would be greatly
appreciated if you could push it to Fedora 24 as well.
If anything is unclear, or if you need any kind of assistance, you can
ask on IRC (#fedora-python on Freenode), or reply here. We'll be happy
to help investigating or fixing this issue!
This is fully intentional. Main codebase of Pungi is Python 2 only (mostly due to dependency on koji). However, there is a separate script that depends on pylorax, which is Python 3 only. This script is invoked at runtime as a subprocess.
See here for some more details:
It is used here:
What we could do is split this single script into a subpackage on its own, but the main package would still have to depend on it. Is that desirable? What advantages would it have?
Invoking it as a subprocess is fine, I apologize for a misfiled bug. In the vast majority of cases needing both Python stacks is a mistake, but in this case it does make sense.
That is not to say it wouldn't be better to have it all run entirely on Python 3, as Python 2 will be end-of-life quite soon and Fedora 25 will be distancing itself away from it as possible. Hopefully, upstream finds the time to port it in the future.
Thank you for the feedback!