[fedora-arm] Trying to upgrade to Fedora 26, but had power issues

I am getting errors on my Rasberry PI 3 after upgrading from Fedora 25 to 26. When I issue the DNF command, I get the following error:

Traceback (most recent call last): File "/usr/bin/dnf", line 57, in <module> from dnf.cli import main

I followed the following instruction: 

https://fedoramagazine.org/upgrading-fedora-25-fedora-26/

But, my Pi had some power issues, and the upgrade got interrupted. Is there any way to recover from this without losing my data?

Thanks,

Rafael