Setting up software-properties-kde (0.96.7) ...
  File "/usr/lib/python3/dist-packages/softwareproperties/kde/SoftwarePropertiesKDE.py", line 732
    text = "%s\n\n<small>%s</small>") % primary, msg
                                    ^
SyntaxError: invalid syntax

dpkg: error processing package software-properties-kde (--configure):
 subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
 software-properties-kde
E: Sub-process /usr/bin/dpkg returned an error code (1)