The PyXB 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 bug appears to have been reported against 'rawhide' during the Fedora 25 development cycle.
Changing version to '25'.
This package has changed ownership in the Fedora Package Database. Reassigning to the new owner of this component.
how is it going? Do you need some help?
This was fixed in [commit a6b24c5]. Thanks Marcus!
[commit a6b24c5]: http://pkgs.fedoraproject.org/cgit/rpms/PyXB.git/commit/PyXB.spec?id=a6b24c501a79b325c9cef3f44fb734ac29aa11ef
Nice to hear that it works. I'll lock into fixing it on F24 as well.