Seems to be related to a new naming of the ‘isAlive()‘ method to ‘is_Alive()‘. See https://bugs.launchpad.net/hplip/+bug/1889280 where a quick workaround is proposed while waiting to an upstream fix:
sudo sed -i 's/isAlive()/is_alive()/g' /usr/share/hplip/*/{copier.py,fax.py,pmlfax.py,sane.py}
